阅读说明：本技术 一种太阳能电池及制备方法 (Solar cell and preparation method thereof ) 是由 黄文洋 于 2019-03-29 设计创作，主要内容包括：本发明实施例公开一种太阳能电池及制备方法。其中,所述太阳能电池包括：包括由下到上依次层叠排列的衬底、至少两节子电池和接触层,在相邻两节子电池之间设置一个隧穿结,隧穿结包括层叠排列的n型第一掺杂层、n型第二掺杂层、p型第一掺杂层和p型第二掺杂层,n型第一掺杂层和n型第二掺杂层相邻,p型第一掺杂层和p型第二掺杂层相邻,n型第一掺杂层和p型第一掺杂层相邻；n型第一掺杂层的n型离子的掺杂浓度高于n型第二掺杂层的掺杂浓度,p型第一掺杂层的p型离子的掺杂浓度高于p型第二掺杂层的掺杂浓度。所述制备方法用于制备上述太阳能电池。本发明实施例提供的太阳能电池及制备方法,提高了太阳能电池的光电转换效率。(The embodiment of the invention discloses a solar cell and a preparation method thereof. Wherein the solar cell includes: the tunneling junction comprises an n-type first doping layer, an n-type second doping layer, a p-type first doping layer and a p-type second doping layer which are arranged in a stacked mode, wherein the n-type first doping layer is adjacent to the n-type second doping layer, the p-type first doping layer is adjacent to the p-type second doping layer, and the n-type first doping layer is adjacent to the p-type first doping layer; the doping concentration of the n-type ions of the n-type first doping layer is higher than that of the n-type second doping layer, and the doping concentration of the p-type ions of the p-type first doping layer is higher than that of the p-type second doping layer. The preparation method is used for preparing the solar cell. The solar cell and the preparation method provided by the embodiment of the invention improve the photoelectric conversion efficiency of the solar cell.)

1. A solar cell comprises a substrate, at least two sub-cells and a contact layer which are sequentially stacked from bottom to top, wherein a tunneling junction is arranged between every two adjacent sub-cells, and the tunneling junction comprises:

the semiconductor device comprises an n-type first doping layer, an n-type second doping layer, a p-type first doping layer and a p-type second doping layer which are arranged in a stacked mode, wherein the n-type first doping layer is adjacent to the n-type second doping layer, the p-type first doping layer is adjacent to the p-type second doping layer, and the n-type first doping layer is adjacent to the p-type first doping layer; the doping concentration of the n-type ions of the n-type first doping layer is higher than that of the n-type ions of the n-type second doping layer, and the doping concentration of the p-type ions of the p-type first doping layer is higher than that of the p-type ions of the p-type second doping layer;

or an n-type third doping layer, an n-type fourth doping layer and a p-type fifth doping layer which are arranged in a stacked mode, wherein the n-type third doping layer is adjacent to the n-type fourth doping layer, and the n-type fourth doping layer is adjacent to the p-type fifth doping layer; the doping concentration of the n-type ions of the n-type fourth doping layer is higher than that of the n-type ions of the n-type third doping layer;

or a p-type third doping layer, a p-type fourth doping layer and an n-type fifth doping layer which are arranged in a stacked mode, wherein the p-type third doping layer is adjacent to the p-type fourth doping layer, and the p-type fourth doping layer is adjacent to the n-type fifth doping layer; wherein the doping concentration of the p-type ions of the p-type fourth doping layer is higher than that of the p-type ions of the p-type third doping layer.

2. The solar cell according to claim 1, wherein the thickness of the n-type second doped layer is 2 to 5nm, the thickness of the n-type first doped layer is 5 to 10nm, the thickness of the p-type second doped layer is 2 to 5nm, and the thickness of the p-type first doped layer is 5 to 10 nm; or

The thickness of the n-type third doping layer is 2-5 nm, the thickness of the n-type fourth doping layer is 5-10 nm, and the thickness of the p-type fifth doping layer is 2-5 nm; or

The thickness of the p-type third doping layer is 2-5 nm, the thickness of the p-type fourth doping layer is 5-10 nm, and the thickness of the n-type fifth doping layer is 2-5 nm.

3. The solar cell of claim 1, wherein the n-type second doped layer is n-type Al_xIn_(1-x)A P layer, the n-type first doping layer is n-type Al_yIn_(1-y)A P layer, the P type first doping layer is P type Al_zIn_(1-z)A P layer, the P-type second doping layer is P-type Al_wIn_(1-w)P layer, wherein x is more than 0.25 and less than 0.55, y is more than 0.25 and less than 0.55, z is more than 0.25 and less than 0.55, w is more than 0.25 and less than 0.55; or

The n-type third doping layer is n-type Al_aIn_(1-a)The P layer and the n-type fourth doped layer are made of n-type Al_bIn_(1-b)A P layer, the P-type fifth doped layer is P-type Al_cIn_(1-c)A is more than 0.25 and less than 0.55, b is more than 0.25 and less than 0.55, and c is more than 0.25 and less than 0.55; or

The p-type third doped layer is pType Al_dIn_(1-d)A P layer, the P-type fourth doped layer is P-type Al_fIn_(1-f)A P layer, the P-type fifth doped layer is P-type Al_gIn_(1-g)And the P layer, wherein d is more than 0.25 and less than 0.55, f is more than 0.25 and less than 0.55, and g is more than 0.25 and less than 0.55.

4. The solar cell of claim 1, wherein the doping concentration of n-type ions in the n-type second doping layer is 5E 17-5E 18/cm³The doping concentration of n-type ions of the n-type first doping layer is 2E 19-2E 20 ions/cm³The doping concentration of the p-type ions of the p-type second doping layer is 5E 17-5E 18 ions/cm³The doping concentration of the p-type ions of the p-type first doping layer is 2E 19-2E 20 ions/cm³(ii) a Or

The doping concentration of n-type ions of the n-type third doping layer is 5E 17-5E 18 ions/cm³The doping concentration of n-type ions of the n-type fourth doping layer is 2E 19-2E 20 ions/cm³The doping concentration of p-type ions of the p-type fifth doping layer is 5E 17-5E 18 ions/cm³Or is or

The doping concentration of p-type ions of the p-type third doping layer is 5E 17-5E 18 ions/cm³The doping concentration of p-type ions of the p-type fourth doping layer is 2E 19-2E 20 ions/cm³The doping concentration of n-type ions of the n-type fifth doping layer is 5E 17-5E 18 ions/cm³。

5. A method for preparing a solar cell according to any one of claims 1 to 4, comprising the following steps of preparing a tunnel junction:

when the substrate is a p-type substrate, sequentially growing an n-type second doping layer, an n-type first doping layer, a p-type first doping layer and a p-type second doping layer from bottom to top; the doping concentration of the n-type ions of the n-type first doping layer is higher than that of the n-type ions of the n-type second doping layer, and the doping concentration of the p-type ions of the p-type first doping layer is higher than that of the p-type ions of the p-type second doping layer;

or when the substrate is a p-type substrate, sequentially growing an n-type third doping layer, an n-type fourth doping layer and a p-type fifth doping layer from bottom to top; the doping concentration of the n-type ions of the n-type fourth doping layer is higher than that of the n-type ions of the n-type third doping layer;

or when the substrate is a p-type substrate, growing the n-type fifth doping layer, the p-type fourth doping layer and the p-type third doping layer from bottom to top in sequence; the doping concentration of the p-type ions of the p-type fourth doping layer is higher than that of the n-type ions of the p-type third doping layer;

or when the substrate is an n-type substrate, growing the p-type second doping layer, the p-type first doping layer, the n-type first doping layer and the n-type second doping layer from bottom to top in sequence; the doping concentration of the n-type ions of the n-type first doping layer is higher than that of the n-type ions of the n-type second doping layer, and the doping concentration of the n-type ions of the n-type first doping layer is higher than that of the n-type ions of the n-type second doping layer;

or when the substrate is an n-type substrate, growing the p-type third doping layer, the p-type fourth doping layer and the n-type fifth doping layer from bottom to top in sequence; the doping concentration of the n-type ions of the n-type fourth doping layer is higher than that of the n-type ions of the n-type third doping layer;

or when the substrate is an n-type substrate, growing the p-type fifth doping layer, the n-type fourth doping layer and the n-type third doping layer from bottom to top in sequence; and the doping concentration of the n-type ions of the n-type fourth doping layer is higher than that of the n-type ions of the n-type third doping layer.

6. The method according to claim 5, wherein the growth temperature conditions of the n-type first doped layer and the p-type first doped layer are 500 to 650 degrees centigrade, and the growth temperature conditions of the n-type second doped layer and the p-type second doped layer are 700 to 830 degrees centigrade; or

The growth temperature conditions of the n-type third doping layer and the p-type fifth doping layer are 500-650 ℃, and the growth temperature condition of the n-type fourth doping layer is 700-830 ℃; or

The growth temperature conditions of the p-type third doping layer and the n-type fifth doping layer are 500-650 ℃, and the growth temperature condition of the p-type fourth doping layer is 700-830 ℃.

7. The method according to claim 5 or 6, wherein the growth rate of the n-type second doped layer is 0.5 to 2nm/s, the growth rate of the n-type first doped layer is 0.2 to 1nm/s, the growth rate of the P-type first doped layer is 0.2 to 1nm/s, and the growth rate of the P-type second doped layer is 0.5 to 2 nm/s; or

The growth rate of the n-type fourth doping layer is 0.5-2 nm/s, the growth rate of the n-type third doping layer is 0.2-1 nm/s, and the growth rate of the p-type fifth doping layer is 0.2-1 nm/s; or

The growth rate of the p-type fourth doping layer is 0.5-2 nm/s, the growth rate of the p-type third doping layer is 0.2-1 nm/s, and the growth rate of the n-type fifth doping layer is 0.2-1 nm/s.

Technical Field

The embodiment of the invention relates to the technical field of semiconductors, in particular to a solar cell and a preparation method thereof.

Background

The gallium arsenide solar cell has good spectral responsiveness, and is generally applied to the fields of aerospace, concentrating photovoltaic power stations and the like.

The gallium arsenide solar cell is formed by connecting a plurality of sub-cells in series, each sub-cell is connected in series by a tunneling junction, the energy band of each sub-cell is sequentially raised from bottom to top, and light with different wavelengths is respectively absorbed, so that full-spectrum absorption is realized. However, most of the tunnel junctions of the existing GaAs solar cells use GaAs (GaAs) or aluminum gallium arsenide (AlGaAs) materials, and the light transmittance of the tunnel junctions is not ideal, so that the light that is not absorbed by the upper subcell is transmitted to the lower subcell less, and the photoelectric conversion efficiency is not high.

Therefore, it is an important issue to be solved in the industry how to provide a solar cell that can use a tunnel junction with good light transmittance to improve the photoelectric conversion efficiency of the solar cell.

Disclosure of Invention

Aiming at the defects in the prior art, the embodiment of the invention provides a solar cell and a preparation method thereof.

In one aspect, an embodiment of the present invention provides a solar cell, including a substrate, at least two sub-cells, and a contact layer, which are sequentially stacked from bottom to top, where a tunnel junction is disposed between two adjacent sub-cells, where the tunnel junction includes:

the semiconductor device comprises an n-type first doping layer, an n-type second doping layer, a p-type first doping layer and a p-type second doping layer which are arranged in a stacked mode, wherein the n-type first doping layer is adjacent to the n-type second doping layer, the p-type first doping layer is adjacent to the p-type second doping layer, and the n-type first doping layer is adjacent to the p-type first doping layer; the doping concentration of the n-type ions of the n-type first doping layer is higher than that of the n-type ions of the n-type second doping layer, and the doping concentration of the p-type ions of the p-type first doping layer is higher than that of the p-type ions of the p-type second doping layer;

or an n-type third doping layer, an n-type fourth doping layer and a p-type fifth doping layer which are arranged in a stacked mode, wherein the n-type third doping layer is adjacent to the n-type fourth doping layer, and the n-type fourth doping layer is adjacent to the p-type fifth doping layer; the doping concentration of the n-type ions of the n-type fourth doping layer is higher than that of the n-type ions of the n-type third doping layer;

or a p-type third doping layer, a p-type fourth doping layer and an n-type fifth doping layer which are arranged in a stacked mode, wherein the p-type third doping layer is adjacent to the p-type fourth doping layer, and the p-type fourth doping layer is adjacent to the n-type fifth doping layer; wherein the doping concentration of the p-type ions of the p-type fourth doping layer is higher than that of the p-type ions of the p-type third doping layer.

In another aspect, an embodiment of the present invention provides a method for manufacturing a solar cell as in the above embodiment, including the following steps:

when the substrate is a p-type substrate, sequentially growing an n-type second doping layer, an n-type first doping layer, a p-type first doping layer and a p-type second doping layer from bottom to top; the doping concentration of the n-type ions of the n-type first doping layer is higher than that of the n-type ions of the n-type second doping layer, and the doping concentration of the p-type ions of the p-type first doping layer is higher than that of the p-type ions of the p-type second doping layer;

or when the substrate is a p-type substrate, sequentially growing an n-type third doping layer, an n-type fourth doping layer and a p-type fifth doping layer from bottom to top; the doping concentration of the n-type ions of the n-type fourth doping layer is higher than that of the n-type ions of the n-type third doping layer;

or when the substrate is a p-type substrate, growing the n-type fifth doping layer, the p-type fourth doping layer and the p-type third doping layer from bottom to top in sequence; the doping concentration of the p-type ions of the p-type fourth doping layer is higher than that of the n-type ions of the p-type third doping layer;

or when the substrate is an n-type substrate, growing the p-type second doping layer, the p-type first doping layer, the n-type first doping layer and the n-type second doping layer from bottom to top in sequence; the doping concentration of the n-type ions of the n-type first doping layer is higher than that of the n-type ions of the n-type second doping layer, and the doping concentration of the n-type ions of the n-type first doping layer is higher than that of the n-type ions of the n-type second doping layer;

or when the substrate is an n-type substrate, growing the p-type third doping layer, the p-type fourth doping layer and the n-type fifth doping layer from bottom to top in sequence; the doping concentration of the n-type ions of the n-type fourth doping layer is higher than that of the n-type ions of the n-type third doping layer;

or when the substrate is an n-type substrate, growing the p-type fifth doping layer, the n-type fourth doping layer and the n-type third doping layer from bottom to top in sequence; and the doping concentration of the n-type ions of the n-type fourth doping layer is higher than that of the n-type ions of the n-type third doping layer.

According to the solar cell and the preparation method provided by the embodiment of the invention, the tunneling junction adopts the structure that the n-type first doping layer, the n-type second doping layer, the p-type first doping layer and the p-type second doping layer are arranged in a stacked mode, the n-type first doping layer is adjacent to the n-type second doping layer, the p-type first doping layer is adjacent to the p-type second doping layer, and the n-type first doping layer is adjacent to the p-type first doping layer, so that the current conduction between two sub-cells adjacent to the tunneling junction is facilitated, and the photoelectric conversion efficiency of the solar cell is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a solar cell according to a first embodiment of the present invention;

fig. 2 is a schematic structural diagram of a solar cell according to a second embodiment of the present invention;

fig. 3 is a schematic structural diagram of a solar cell according to a third embodiment of the present invention;

fig. 4 is a schematic structural diagram of a solar cell according to a fourth embodiment of the invention;

fig. 5 is a schematic structural diagram of a solar cell according to a fifth embodiment of the present invention;

fig. 6 is a schematic structural diagram of a solar cell according to a sixth embodiment of the invention;

fig. 7 is a schematic structural diagram of a solar cell according to a seventh embodiment of the invention;

fig. 8 is a schematic structural diagram of a solar cell according to an eighth embodiment of the present invention;

fig. 9 is a schematic structural diagram of a solar cell according to a ninth embodiment of the present invention;

fig. 10 is a schematic structural diagram of a solar cell according to a tenth embodiment of the present invention;

fig. 11 is a schematic flow chart of a method for manufacturing a solar cell according to an eleventh embodiment of the present invention;

fig. 12 is a schematic flow chart illustrating a method for manufacturing a solar cell according to a twelfth embodiment of the present invention;

fig. 13a is a schematic view of a bottom cell fabrication of a solar cell according to a thirteenth embodiment of the present invention;

fig. 13b is a schematic view illustrating the preparation of an n-type second doped layer of a tunnel junction according to a thirteenth embodiment of the invention;

fig. 13c is a schematic view illustrating the preparation of an n-type first doped layer of a tunnel junction according to a thirteenth embodiment of the invention;

fig. 13d is a schematic view illustrating the preparation of a p-type first doped layer of a tunneling junction according to a thirteenth embodiment of the present invention;

fig. 13e is a schematic view illustrating the preparation of a p-type second doped layer of a tunneling junction according to a thirteenth embodiment of the present invention;

fig. 13f is a schematic diagram of a middle cell fabrication of a solar cell provided in a thirteenth embodiment of the invention;

fig. 13g is a schematic view illustrating a tunneling junction according to a thirteenth embodiment of the present invention;

fig. 13h is a schematic diagram illustrating the preparation of a top cell and a contact layer of a solar cell according to a thirteenth embodiment of the present invention;

fig. 14 is a schematic flow chart of a method for manufacturing a solar cell according to a fourteenth embodiment of the invention;

fig. 15 is a schematic flow chart of a method for manufacturing a solar cell according to a fifteenth embodiment of the invention;

fig. 16 is a schematic flow chart illustrating a method for manufacturing a solar cell according to a sixteenth embodiment of the present invention;

fig. 17 is a schematic flow chart of a method for manufacturing a solar cell according to a seventeenth embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Fig. 1 is a schematic structural diagram of a solar cell according to an embodiment of the present invention, and as shown in fig. 1, the solar cell according to the embodiment of the present invention includes: from bottom to top in proper order range upon range of substrate 1, two section at least subcells 2 and contact layer 4 of arranging, set up a tunneling junction 3 between two adjacent subcells 2, tunneling junction 3 includes:

the n-type first doping layer 32, the n-type second doping layer 31, the p-type first doping layer 33 and the p-type second doping layer 34 are arranged in a stacked mode, the n-type first doping layer 32 is adjacent to the n-type second doping layer 31, the p-type first doping layer 33 is adjacent to the p-type second doping layer 34, and the n-type first doping layer 32 is adjacent to the p-type first doping layer 33; the doping concentration of n-type ions in the n-type first doping layer 32 is higher than that of n-type ions in the n-type second doping layer 31, and the doping concentration of p-type ions in the p-type first doping layer 33 is higher than that of p-type ions in the p-type second doping layer 34.

Specifically, the substrate 1 may be a p-type substrate or an n-type substrate, and when the substrate 1 is a p-type substrate, the n-type first doping layer 32, the n-type second doping layer 31, the p-type first doping layer 33 and the p-type second doping layer 34 are sequentially stacked from bottom to top in the order of the n-type second doping layer 31, the n-type first doping layer 32, the p-type first doping layer 33 and the p-type second doping layer 34; when the substrate 1 is an n-type substrate, the n-type first doping layer 32, the n-type second doping layer 31, the p-type first doping layer 33 and the p-type second doping layer 34 are sequentially stacked from bottom to top in the order of the p-type second doping layer 34, the p-type first doping layer 33, the n-type first doping layer 32 and the n-type second doping layer 31. The specific structures of the sub-cells 2 and the contact layer 4 are set according to actual needs, and the embodiment of the invention is not limited.

For example, fig. 2 is a schematic structural diagram of a solar cell according to a second embodiment of the present invention, and as shown in fig. 2, the solar cell according to the embodiment of the present invention includes a substrate 21 and three sub-cells, which are sequentially stacked from bottom to top: the cell structure comprises a bottom cell 22, a middle cell 23, a top cell 24, and a contact layer 25, wherein a tunneling junction 26 is arranged between the bottom cell 22 and the middle cell 23, a tunneling junction 27 is arranged between the middle cell 23 and the top cell 24, the bottom cell 22 comprises an emitter layer 221 and a window layer 222 which are sequentially stacked from bottom to top, the middle cell 23 comprises a back layer 231, a base region 232, an emitter layer 233, and a window layer 234 which are sequentially stacked from bottom to top, the top cell 24 comprises a back layer 241, a base region 242, an emitter layer 243, and a window layer 244 which are sequentially stacked from bottom to top, the tunneling junction 26 comprises an n-type second doping layer 261, an n-type first doping layer 262, a p-type first doping layer 263, and a p-type second doping layer 264 which are sequentially stacked from bottom to top, and the tunneling junction 27 and the p-type second doping layer 264 have the same structure.

Wherein, the substrate 21 adopts a P-type germanium (Ge) layer, the emission layer 221 adopts an n-type Ge layer, the window layer 222 adopts an n-type gallium indium phosphide (GaInP) layer, the back layer 231 adopts a P-type GaInP layer, the base region 232 adopts a P-type GaAs layer, the emission layer 233 adopts an n-type GaAs layer, the window layer 234 adopts an n-type aluminum gallium indium phosphide (AlGaInP) layer, the back layer 241 adopts a P-type GaInP layer, the base region 242 adopts a P-type GaInP layer, the emission layer 243 adopts an n-type GaInP layer, the window layer 244 adopts an n-type AlGaInP layer,the contact layer 25 is an n-type GaAs layer. The n-type first doping layer 262 may be n-type Al_0.4In_0.6The P layer and the n-type second doping layer 261 can adopt n-type Al_0.4In_0.6For the P layer and the P-type first doping layer 263, Al may be used_0.3In_0.7P, P-type second doping layer 264 may be made of P-type Al_0.3In_0.7And a P layer.

For example, fig. 3 is a schematic structural diagram of a solar cell according to a third embodiment of the present invention, and as shown in fig. 3, the solar cell according to the embodiment of the present invention includes a substrate 301 and two sub-cells, which are sequentially stacked from bottom to top: the bottom cell 302, the top cell 303 and the contact layer 304, wherein a tunneling junction 305 is arranged between the bottom cell 302 and the top cell 303, the bottom cell 302 comprises a back layer 3021, a base region 3022, an emitter layer 3023 and a window layer 3024 which are sequentially stacked from bottom to top, the top cell 303 comprises a back layer 3031, a base region 3032, an emitter layer 3033 and a window layer 3034 which are sequentially stacked from bottom to top, and the tunneling junction 305 comprises an n-type second doped layer 3051, an n-type first doped layer 3052, a p-type first doped layer 3053 and a p-type second doped layer 3054 which are sequentially stacked from bottom to top.

The substrate 301 adopts a P-type Ge layer, the back layer 3021 adopts a P-type GaInP layer, the base region 3022 adopts a P-type GaAs layer, the emission layer 3023 adopts an n-type GaAs layer, the window layer 3024 adopts an n-type AlGaInP layer, the back layer 3031 adopts a P-type GaInP layer, the base region 3032 adopts a P-type GaInP layer, the emission layer 3033 adopts an n-type GaInP layer, the window layer 3034 adopts an n-type AlGaInP layer, and the contact layer 304 adopts an n-type GaAs layer. The n-type first doped layer 3052 may be made of n-type Al_0.5In_0.5The P-type and n-type second doped layer 3051 may be made of n-type Al_0.4In_0.6Al may be used for the P layer and the P-type first doping layer 3053_0.3In_0.7P-type Al can be used for the P-and P-type second doped layer 3054_0.35In_0.65And a P layer.

For example, fig. 4 is a schematic structural diagram of a solar cell according to a fourth embodiment of the present invention, and as shown in fig. 4, the solar cell according to the embodiment of the present invention includes a substrate 41 and four sub-cells, which are sequentially stacked from bottom to top: first sub-battery 42, second sub-battery 43, third sub-battery 44, and fourth sub-batteryA cell 45, and a contact layer 46, with a tunnel junction 47 between the first subcell 42 and the second subcell 43, a tunnel junction 48 between the second subcell 43 and the third subcell 44, and a tunnel junction 49 between the third subcell 44 and the fourth subcell 45. The substrate 41 may be a P-type germanium substrate, and each of the sub-cells may be arranged according to actual needs, for example, the first sub-cell 42 may be a Ge sub-cell, the second sub-cell 43 may be a GaInNAs sub-cell, the third sub-cell 44 may be a GaAs sub-cell, and the fourth sub-cell 45 may be a GaInP sub-cell. The tunneling junction 48 includes an n-type second doped layer 481, an n-type first doped layer 482, a p-type first doped layer 483 and a p-type second doped layer 484, which are stacked, and the n-type first doped layer 482 may be made of n-type Al_0.5In_0.5The P-type and n-type second doped layer 481 may be made of n-type Al_0.5In_0.5The P-type and P-type first doping layers 483 may be made of Al_0.5In_0.5P-type Al may be used for the P-and P-type second doping layer 484_0.5In_0.5And a P layer. The tunnel junctions 47 and 49 may adopt the same structure as the tunnel junction 48.

According to the solar cell provided by the embodiment of the invention, the tunneling junction adopts the n-type first doping layer, the n-type second doping layer, the p-type first doping layer and the p-type second doping layer which are arranged in a stacked manner, the n-type first doping layer is adjacent to the n-type second doping layer, the p-type first doping layer is adjacent to the p-type second doping layer, and the n-type first doping layer is adjacent to the p-type first doping layer, so that the current conduction between two sub-cells adjacent to the tunneling junction is facilitated, and the photoelectric conversion efficiency of the solar cell is improved.

In addition to the above embodiments, the thickness of the n-type second doped layer 31 is 2 to 5nm, such as 3nm, the thickness of the n-type first doped layer 32 is 5 to 10nm, such as 8nm, the thickness of the p-type second doped layer 34 is 2 to 5nm, such as 4nm, and the thickness of the p-type first doped layer 33 is 5 to 10nm, such as 7 nm.

In addition to the above embodiments, the n-type second doped layer 31 is n-type Al_xIn_(1-x)The P layer and the n-type first doping layer 32 are made of n-type Al_yIn_(1-y)P layer, P-type first doping layer 33 is P-type Al_zIn_(1-z)P-type second doping layer 34 is P-type Al_wIn_(1-w)And the P layer, wherein x is more than 0.25 and less than 0.55, y is more than 0.25 and less than 0.55, z is more than 0.25 and less than 0.55, and w is more than 0.25 and less than 0.55. The aluminum indium phosphide (AlInP) material has better light transmittance, so that more sunlight which is not absorbed by the upper layer sub-cell can enter the lower layer sub-cell, and the photoelectric conversion efficiency of the solar cell is further improved.

In addition to the above embodiments, the doping concentration of n-type ions in the n-type second doping layer 31 is 5E 17-5E 18/cm³The doping concentration of n-type ions in the n-type first doping layer 32 is 2E 19-2E 20 ions/cm³The doping concentration of the p-type ions in the p-type second doping layer 34 is 5E 17-5E 18 ions/cm³The doping concentration of the p-type ions in the p-type first doping layer 33 is 2E 19-2E 20 ions/cm³. The doping concentrations of the n-type second doping layer 31 and the p-type second doping layer 34 are low, so that the influence on the doping concentrations of the adjacent sub-cells can be reduced, and the doping concentrations of the n-type first doping layer 32 and the p-type first doping layer 33 are high, so that the current conduction between the two adjacent sub-cells is facilitated.

Fig. 5 is a schematic structural diagram of a solar cell according to a fifth embodiment of the present invention, fig. 6 is a schematic structural diagram of a solar cell according to a sixth embodiment of the present invention, as shown in fig. 5 and fig. 6, the solar cell according to the embodiment of the present invention includes a substrate 51, at least two sub-cells 52, and a contact layer 54, which are sequentially stacked from bottom to top, and a tunneling junction 53 is disposed between two adjacent sub-cells 52, as shown in fig. 5, the tunneling junction 53 includes:

an n-type third doping layer 531, an n-type fourth doping layer 532 and a p-type fifth doping layer 533 which are arranged in a stacked manner, wherein the n-type third doping layer 531 is adjacent to the n-type fourth doping layer 532, and the n-type fourth doping layer 532 is adjacent to the p-type fifth doping layer 533; wherein, the doping concentration of n-type ions of the n-type fourth doping layer 532 is higher than that of the n-type third doping layer 531;

specifically, the substrate 1 may be a p-type substrate or an n-type substrate, and when the substrate 1 is a p-type substrate, the n-type third doping layer 531, the n-type fourth doping layer 532 and the p-type fifth doping layer 533 are sequentially stacked from bottom to top, and are sequentially arranged as the n-type third doping layer 531, the n-type fourth doping layer 532 and the p-type fifth doping layer 533; when the substrate 1 is an n-type substrate, the n-type third doping layer 531, the n-type fourth doping layer 532 and the p-type fifth doping layer 533 are sequentially stacked from bottom to top in the order of the p-type fifth doping layer 533, the n-type fourth doping layer 532 and the n-type third doping layer 531. The specific structures of the sub-cells 52 and the contact layer 54 are set according to actual needs, and the embodiment of the invention is not limited thereto.

For example, fig. 7 is a schematic structural diagram of a solar cell according to a seventh embodiment of the present invention, and as shown in fig. 7, the solar cell according to the embodiment of the present invention includes a substrate 71 and three sub-cells, which are sequentially stacked from bottom to top: the cell structure comprises a bottom cell 72, a middle cell 73, a top cell 74 and a contact layer 75, wherein a tunneling junction 76 is arranged between the bottom cell 72 and the middle cell 73, the structure of the tunneling junction arranged between the middle cell 73 and the top cell 74 is the same as that of the tunneling junction 76, the bottom cell 72 can adopt the structure of the bottom cell 22 shown in fig. 2, the middle cell 73 can adopt the structure of the middle cell 23 shown in fig. 2, the top cell 74 can adopt the structure of the top cell 74 shown in fig. 2, the tunneling junction 76 comprises an n-type third doping layer 761, an n-type fourth doping layer 762 and a p-type fifth doping layer 763 which are sequentially stacked from bottom to top, and the n-type third doping layer 761 can adopt n-type Al_0.4In_0.6The P-type and n-type fourth doping layers 762 can be made of n-type Al_0.4In_0.6The P-type fifth doping layer 763 can be made of Al_0.3In_0.7P。

For example, fig. 8 is a schematic structural diagram of a solar cell according to an eighth embodiment of the present invention, and as shown in fig. 8, the solar cell according to the embodiment of the present invention includes a substrate 81 and two sub-cells, which are sequentially stacked from bottom to top: a bottom cell 82, a top cell 83, and a contact layer 84, wherein a tunnel junction 85 is disposed between the bottom cell 82 and the top cell 83, the bottom cell 82 may adopt the structure of a bottom cell 302 as shown in fig. 3, the top cell 83 may adopt the structure of a top cell 303 as shown in fig. 3, and the tunnel junction 85 includes an n-type third doped layer 851, an n-type fourth doped layer 852, and a p-type fifth doped layer 851, which are sequentially stacked from bottom to topDoped layer 853. The substrate 301 is a P-type Ge layer, and the n-type third doping layer 851 may be n-type Al_0.5In_0.5The P-type and n-type fourth doped layer 852 can be made of n-type Al_0.4In_0.6Al can be used for the P-type and P-type fifth doping layer 853_0.3In_0.7P。

According to the solar cell provided by the embodiment of the invention, the tunneling junction adopts the n-type third doping layer, the n-type fourth doping layer and the p-type fifth doping layer which are arranged in a stacked manner, the n-type third doping layer is adjacent to the n-type fourth doping layer, and the p-type fifth doping layer is adjacent to the n-type fourth doping layer, so that the current conduction between two sub-cells adjacent to the tunneling junction is facilitated, and the photoelectric conversion efficiency of the solar cell is improved.

As shown in fig. 6, the tunneling junction 53 may include: a p-type third doping layer 534, a p-type fourth doping layer 535 and an n-type fifth doping layer 536 which are arranged in a stacked manner, wherein the p-type third doping layer 534 is adjacent to the p-type fourth doping layer 535, and the p-type fourth doping layer 535 is adjacent to the n-type fifth doping layer 536; the doping concentration of p-type ions in p-type fourth doped layer 535 is higher than that of p-type ions in p-type third doped layer 534.

Specifically, the substrate 1 may be a p-type substrate or an n-type substrate, and when the substrate 1 is a p-type substrate, the p-type third doping layer 534, the p-type fourth doping layer 535, and the n-type fifth doping layer 536 are sequentially stacked from bottom to top in the order of the p-type third doping layer 534, the p-type fourth doping layer 535, and the n-type fifth doping layer 536; when the substrate 1 is an n-type substrate, the p-type third doping layer 534, the p-type fourth doping layer 535 and the n-type fifth doping layer 536 are sequentially stacked from bottom to top in the order of the n-type fifth doping layer 536, the p-type fourth doping layer 535 and the p-type third doping layer 534.

For example, fig. 9 is a schematic structural diagram of a solar cell according to a seventh embodiment of the present invention, and as shown in fig. 9, the solar cell according to the embodiment of the present invention includes a substrate 71 and three sub-cells, which are sequentially stacked from bottom to top: a bottom cell 72, a middle cell 73, a top cell 74, and a contact layer 75, a tunnel junction 76 disposed between the bottom cell 72 and the middle cell 73, and a tunnel and a structure of the tunnel junction disposed between the middle cell 73 and the top cell 74The tunneling junction 76 is the same, the bottom cell 72 may adopt the structure of the bottom cell 22 shown in fig. 2, the middle cell 73 may adopt the structure of the middle cell 23 shown in fig. 2, the top cell 74 may adopt the structure of the top cell 74 shown in fig. 2, the tunneling junction 76 includes a p-type third doped layer 764, a p-type fourth doped layer 765 and an n-type fifth doped layer 766 which are sequentially stacked from bottom to top, and the n-type third doped layer 764 adopts p-type Al_0.4In_0.6P-type Al can be used as the P-type fourth doped layer 765_0.4In_0.6Al may be used for the P-type and n-type fifth doping layer 766_0.3In_0.7P。

For example, fig. 10 is a schematic structural diagram of a solar cell according to a tenth embodiment of the present invention, and as shown in fig. 10, the solar cell according to the embodiment of the present invention includes a substrate 81 and two sub-cells, which are sequentially stacked from bottom to top: the cell structure comprises a bottom cell 82, a top cell 83 and a contact layer 84, wherein a tunneling junction 85 is arranged between the bottom cell 82 and the top cell 83, the bottom cell 82 can adopt the structure of a bottom cell 302 shown in fig. 3, the top cell 83 can adopt the structure of a top cell 303 shown in fig. 3, and the tunneling junction 85 comprises a p-type third doping layer 854, a p-type fourth doping layer 853 and an n-type fifth doping layer 856 which are sequentially stacked from bottom to top. The substrate 81 adopts a P-type Ge layer, and the P-type third doping layer 854 can adopt P-type Al_0.5In_0.5P-type Al can be used for the P-type fourth doped layer 855_0.4In_0.6The P-type and n-type fifth doped layers 856 may be made of Al_0.3In_0.7P。

According to the solar cell provided by the embodiment of the invention, the tunneling junction adopts the p-type third doping layer, the p-type fourth doping layer and the n-type fifth doping layer which are arranged in a stacked manner, the p-type third doping layer is adjacent to the p-type fourth doping layer, and the n-type fifth doping layer is adjacent to the p-type fourth doping layer, so that the current conduction between two sub-cells adjacent to the tunneling junction is facilitated, and the photoelectric conversion efficiency of the solar cell is improved.

In addition to the above embodiments, the thickness of the n-type third doped layer 531 is 2 to 5nm, such as 3nm, the thickness of the n-type fourth doped layer 532 is 5 to 10nm, such as 8nm, the thickness of the p-type fifth doped layer 533 is 2 to 5nm, such as 4 nm;

in addition to the above embodiments, the thickness of the p-type third doped layer 534 is 2 to 5nm, such as 3nm, the thickness of the p-type fourth doped layer 535 is 5 to 10nm, such as 8nm, and the thickness of the n-type fifth doped layer 536 is 2 to 5nm, such as 4 nm.

In addition to the above embodiments, the n-type third doping layer 531 is n-type Al_aIn_(1-a)The P layer and the n-type fourth doped layer 532 are n-type Al_bIn_(1-b)P layer, P-type fifth doped layer 533 of P-type Al_cIn_(1-c)A is more than 0.25 and less than 0.55, b is more than 0.25 and less than 0.55, and c is more than 0.25 and less than 0.55;

in addition to the above embodiments, the p-type third doped layer 534 is further p-type Al_dIn_(1-d)P layer, P-type fourth doped layer 535 is P-type Al_fIn_(1-f)P layer, n-type fifth doped layer 536 is n-type Al_gIn_(1-g)And the P layer, wherein d is more than 0.25 and less than 0.55, f is more than 0.25 and less than 0.55, and g is more than 0.25 and less than 0.55.

In addition to the above embodiments, the doping concentration of n-type ions in the n-type third doping layer 531 is 5E 17-5E 18/cm³The doping concentration of n-type ions in the n-type fourth doping layer 532 is 2E 19-2E 20 ions/cm³The doping concentration of the p-type ions in the p-type fifth doping layer 533 is 5E 17-5E 18 ions/cm³. The doping concentrations of the n-type third doping layer 531 and the p-type fifth doping layer 533 are low, so that the influence on the doping concentrations of the adjacent sub-cells can be reduced, and the doping concentration of the n-type fourth doping layer 532 is high, so that the current conduction between the two adjacent sub-cells is facilitated.

In addition to the above embodiments, the doping concentration of p-type ions in the p-type third doping layer 534 is 5E 17-5E 18/cm³The doping concentration of p-type ions in the p-type fourth doping layer 535 is 2E 19-2E 20 ions/cm³The doping concentration of n-type ions in the n-type fifth doping layer 536 is 5E 17-5E 18 ions/cm³. The doping concentration of the n-type fifth doping layer 536 and the p-type third doping layer 534 is low, so that the doping concentration of the adjacent sub-cells can be reducedThe influence is caused, and the doping concentration of the n-type fourth doping layer 532 is higher, which is beneficial to the conduction of current between two adjacent sub-cells.

Fig. 11 is a schematic flow chart of a method for manufacturing a solar cell according to an eleventh embodiment of the present invention, and fig. 12 is a schematic flow chart of a method for manufacturing a solar cell according to a twelfth embodiment of the present invention, where as shown in fig. 11 and 12, the method for manufacturing a solar cell according to any one of the above embodiments of the present invention includes a step of manufacturing a tunnel junction as shown in fig. 11 or 12.

When the substrate of the solar cell is a p-type substrate, the preparation steps of the tunneling junction as shown in fig. 11 may be adopted to grow an n-type second doped layer, an n-type first doped layer, a p-type first doped layer, and a p-type second doped layer in sequence from bottom to top, and the specific steps are as follows:

s1101, growing an n-type second doping layer;

specifically, when the tunnel junction between two adjacent sub-cells is fabricated, an n-type second doping layer may be grown on the adjacent lower sub-cell by introducing a silicon (Si) source or a tellurium (Te) source through a Metal-organic Chemical Vapor Deposition (MOCVD) method. The thickness of the n-type second doping layer can be 2-5 nm, and the n-type second doping layer can be made of n-type Al_xIn_(1-x)The P layer, x is more than 0.25 and less than 0.55, and the doping concentration of n-type ions of the n-type second doping layer can be 5E 17-5E 18/cm³。

S1102, growing an n-type first doping layer on the n-type second doping layer, wherein the doping concentration of n-type ions of the n-type first doping layer is higher than that of the n-type ions of the n-type second doping layer;

specifically, after the n-type second doping layer is manufactured, an Si source or a Te source may be introduced through an MOCVD method, and an n-type first doping layer may be grown on the n-type second doping layer, where a doping concentration of n-type ions of the n-type first doping layer is higher than a doping concentration of n-type ions of the n-type second doping layer. Wherein the thickness of the n-type first doped layer can be 5-10 nm, and the n-type first doped layer can ben type Al_yIn_(1-y)Y is more than 0.25 and less than 0.55, and the doping concentration of n-type ions of the n-type first doping layer can be 2E 19-2E 20 ions/cm³Since the n-type first doping layer needs to obtain a higher doping concentration of n-type ions, the flow rate of the introduced Si source or Te source may be increased, for example, the flow rate of the introduced Si source or Te source is 2-5 times that of the Si source or Te source introduced in step S1101.

S1103, growing a p-type first doping layer on the n-type first doping layer;

specifically, after the n-type first doping layer is manufactured, a magnesium (Mg) source or a carbon (C) source may be introduced through an MOCVD method to grow a p-type first doping layer on the n-type first doping layer. The thickness of the p-type first doping layer can be 5-10 nm, and the p-type first doping layer can be p-type Al_zIn_(1-z)The P layer, z is more than 0.25 and less than 0.55, the doping concentration of P-type ions of the P-type first doping layer can be 2E 19-2E 20/cm³。

S1104, growing a p-type second doping layer on the p-type first doping layer, wherein the doping concentration of p-type ions of the p-type first doping layer is higher than that of the p-type ions of the p-type second doping layer;

specifically, after the p-type first doping layer is manufactured, an Mg source or a C source may be introduced through an MOCVD method, and a p-type second doping layer may be grown on the p-type first doping layer, where a doping concentration of p-type ions of the p-type first doping layer is higher than a doping concentration of p-type ions of the p-type second doping layer. The thickness of the p-type second doping layer can be 2-5 nm, and the p-type second doping layer can be p-type Al_wIn_(1-w)A P layer, w is more than 0.25 and less than 0.55, the doping concentration of P-type ions of the P-type second doping layer is 5E 17-5E 18 ions/cm³Since the p-type second doping layer needs to obtain a lower doping concentration of the p-type ions, the flow rate of the introduced Mg source or C source may be reduced, for example, the flow rate of the introduced Mg source or C source is 50% to 80% of the flow rate of the Mg source or C source introduced in step S1103. After the p-type second doping layer is manufactured, an upper part adjacent to the tunneling junction is manufacturedA layer of sub-cells.

When the substrate of the solar cell is an n-type substrate, the p-type second doped layer, the p-type first doped layer, the n-type first doped layer, and the n-type second doped layer may be sequentially grown from bottom to top by using the preparation steps of tunneling junctions as shown in fig. 12, which specifically include the following steps:

s1201, growing the p-type second doping layer;

specifically, when the tunnel junction between two adjacent sub-cells is manufactured, an Mg source or a C source can be introduced through an MOCVD method, and a p-type second doping layer grows on the adjacent lower sub-cell. The thickness of the p-type second doping layer can be 2-5 nm, and the p-type second doping layer can adopt p-type Al_wIn_(1-w)The P layer, w is more than 0.25 and less than 0.55, the doping concentration of P-type ions of the P-type second doping layer can be 5E 17-5E 18/cm³。

S1202, growing the p-type first doping layer on the p-type second doping layer, wherein the doping concentration of p-type ions of the p-type first doping layer is higher than that of the p-type ions of the p-type second doping layer;

specifically, after the p-type second doping layer is manufactured, an Mg source or a C source may be introduced through an MOCVD method, and a p-type first doping layer is grown on the p-type second doping layer, where a doping concentration of p-type ions of the p-type first doping layer is higher than a doping concentration of p-type ions of the p-type second doping layer. The thickness of the p-type first doping layer can be 5-10 nm, and the p-type first doping layer can be p-type Al_zIn_(1-z)The P layer, z is more than 0.25 and less than 0.55, the doping concentration of P-type ions of the P-type first doping layer can be 2E 19-2E 20/cm³Since the p-type first doping layer needs to obtain a higher doping concentration of p-type ions, the flow rate of the introduced Mg source or C source may be increased, for example, the flow rate of the introduced Mg source or C source is 2-5 times that of the Mg source or C source introduced in step S1201.

S1203, growing the n-type first doping layer on the p-type first doping layer;

in particular, in said p-typeAfter the first doping layer is manufactured, a Si source or a Te source can be introduced through an MOCVD method, and the n-type first doping layer is grown on the p-type first doping layer. Wherein the thickness of the n-type first doping layer can be 5-10 nm, and the n-type first doping layer can be Al_yIn_(1-y)Y is more than 0.25 and less than 0.55, and the doping concentration of n-type ions of the n-type first doping layer can be 2E 19-2E 20 ions/cm³。

And S1204, growing the n-type second doping layer on the n-type first doping layer, wherein the doping concentration of the n-type ions of the n-type first doping layer is higher than that of the n-type ions of the n-type second doping layer.

Specifically, after the n-type first doping layer is manufactured, an n-type second doping layer can be grown on the n-type first doping layer by introducing a Si source or a Te source through an MOCVD method, wherein the doping concentration of n-type ions of the n-type first doping layer is higher than that of n-type ions of the n-type second doping layer. The thickness of the n-type second doping layer can be 2-5 nm, and the n-type second doping layer can be n-type Al_xIn_(1-x)X is more than 0.25 and less than 0.55, and the doping concentration of n-type ions of the n-type second doping layer is 5E 17-5E 18 ions/cm³Since the n-type second doping layer needs to obtain a lower doping concentration of n-type ions, the flow rate of the introduced Si source or Te source may be reduced, for example, the flow rate of the introduced Si source or Te source is 50% to 80% of the flow rate of the introduced Si source or Te source in step S1203. After the n-type second doping layer is manufactured, an upper sub-cell adjacent to the tunneling junction is manufactured.

It can be understood that the specific processes for preparing the substrate, each segment cell and the contact layer of the solar cell are the prior art and are not described herein.

According to the preparation method of the solar cell provided by the embodiment of the invention, the manufactured tunneling junction is provided with the n-type first doping layer, the n-type second doping layer, the p-type first doping layer and the p-type second doping layer which are arranged in a stacked mode, the n-type first doping layer is adjacent to the n-type second doping layer, the p-type first doping layer is adjacent to the p-type second doping layer, and the n-type first doping layer is adjacent to the p-type first doping layer, so that current conduction between two sub-cells adjacent to the tunneling junction is facilitated, and the photoelectric conversion efficiency of the solar cell is improved.

In addition to the above embodiments, in the method for manufacturing a solar cell according to the embodiments of the present invention, the growth temperature conditions of the n-type first doping layer and the p-type first doping layer are 500 to 650 degrees celsius, and the growth temperature conditions of the n-type second doping layer and the p-type second doping layer are 700 to 830 degrees celsius.

Specifically, the temperature of the MOCVD reaction chamber can be set to be 500-650 ℃ when growing the n-type first doping layer or the p-type first doping layer, so as to meet the growth temperature condition of the n-type first doping layer or the p-type first doping layer, and the growth temperature of the n-type first doping layer or the p-type first doping layer is set to be 500-650 ℃, which is beneficial to obtaining higher doping concentration. When the n-type second doping layer or the p-type second doping layer grows, the temperature of an MOCVD reaction chamber can be set to be 700-830 ℃ so as to meet the growth temperature condition of the n-type second doping layer or the p-type second doping layer, and the growth temperature of the n-type second doping layer or the p-type second doping layer is set to be 700-830 ℃, so that the n-type second doping layer or the p-type second doping layer with better crystal quality can be obtained.

On the basis of the above embodiments, in the method for manufacturing a solar cell according to the embodiments of the present invention, the growth rate of the n-type second doped layer is 0.5 to 2nm/s, the growth rate of the n-type first doped layer is 0.2 to 1nm/s, the growth rate of the P-type first doped layer is 0.2 to 1nm/s, and the growth rate of the P-type second doped layer is 0.5 to 2 nm/s. Limiting the growth rate of the n-type second doping layer and the growth rate of the p-type second doping layer to 0.5-2 nm/s, and ensuring the product quality of the n-type second doping layer and the p-type second doping layer while ensuring the production efficiency. Limiting the growth rate of the n-type first doping layer and the growth rate of the p-type first doping layer to 0.2-1 nm/s, and ensuring the production efficiency and the product quality of the n-type first doping layer and the p-type first doping layer.

The following describes in detail the process of the method for manufacturing a solar cell according to the embodiment of the present invention, taking a manufacturing process of a solar cell including three solar cells and two tunnel junctions having the same structure as the solar cells as an example.

Fig. 13a is a schematic diagram of a bottom cell preparation of a solar cell according to a thirteenth embodiment of the present invention, as shown in fig. 13a, the solar cell employs a p-type Ge substrate 131, the p-type Ge substrate 131 is placed in an MOCVD reaction chamber, n-type phosphorus diffusion is performed on the upper surface of the p-type Ge substrate 131 to obtain an emission layer 1321 of the bottom cell 132, then an n-type GaInP buffer layer is grown on the emission layer 1321 to obtain a window layer 1322 of the bottom cell 132, and the window layer 1322 plays a role in nucleation;

fig. 13b is a schematic diagram illustrating a preparation process of an n-type second doping layer of a tunnel junction according to a thirteenth embodiment of the present invention, as shown in fig. 13b, the MOCVD reaction chamber is set at 1350 ℃, a silicon source is introduced, and a 3nm thick window layer 1322 is grown with a doping concentration of 1E 18/cm³N-type Al of (1)_0.4In_0.6A P layer, to obtain an n-type second doping layer 1331 of the tunnel junction 133, wherein the growth rate of the n-type second doping layer 1331 is 1 nm/s;

fig. 13c is a schematic view illustrating a preparation process of an n-type first doping layer of a tunnel junction according to a thirteenth embodiment of the present invention, as shown in fig. 13c, a temperature of an MOCVD reaction chamber is decreased to 600 ℃, a flow rate of introducing a silicon source is increased to 3 times of an original flow rate, and an 8nm thick n-type second doping layer 1331 is grown with a doping concentration of 1E 20/cm³N-type Al of (1)_0.4In_0.6A P layer, to obtain an n-type first doping layer 1332 of the tunnel junction 133, the growth rate of the n-type first doping layer 1332 being 0.5 nm/s;

fig. 13d is a schematic view illustrating a process for preparing a p-type first doping layer of a tunnel junction according to a thirteenth embodiment of the present invention, as shown in fig. 13d, the temperature of the MOCVD reactor is kept constant, a magnesium source is introduced, and an n-type first doping layer 1332 is grown to a thickness of 8nm and a doping concentration of 1E 20/cm³N-type Al of (1)_0.4In_0.6P layer to obtain a P-type first doped layer 1333 of the tunnel junction 133, P-type second doped layerThe growth rate of the doped layer 1333 is 0.5 nm/s;

fig. 13E is a schematic diagram illustrating the preparation of the p-type second doping layer of the tunnel junction according to the thirteenth embodiment of the present invention, and as shown in fig. 13E, the temperature of the MOCVD reactor is raised to 1350 ℃, the flow rate of the introduced magnesium source is reduced to 60% of the original flow rate, and a 3nm thick p-type first doping layer 1333 is grown with a doping concentration of 1E 18/cm³P-type Al of (1)_0.4In_0.6A P layer, to obtain a P-type second doping layer 1334 of the tunnel junction 133, wherein the growth rate of the n-type second doping layer 1334 is 1 nm/s;

fig. 13f is a schematic diagram of a middle cell of a solar cell according to a thirteenth embodiment of the invention, as shown in fig. 13f, a p-type GaInP layer is grown on a p-type second doping layer 1334 to serve as a back layer 1341 of the middle cell 134, a p-type GaAs layer is grown on the back layer 1341 to serve as a base region 1342 of the middle cell 134, an n-type GaAs layer is grown on the base region 1342 to serve as an emitter layer 1343 of the middle cell 134, and an n-type AlGaInP layer is grown on the emitter layer 1343 to serve as a window layer 1344 of the middle cell 134. The thicknesses of the back layer 1341, the base region 1342, the emitter layer 1343 and the window layer 1344 included in the middle cell 134 are set according to actual needs, and the embodiment of the present invention is not limited thereto.

Fig. 13g is a schematic diagram illustrating preparation of a tunnel junction according to a thirteenth embodiment of the invention, as shown in fig. 13g, the tunnel junction 135 and the tunnel junction 133 have the same structure, a preparation process of the n-type second doping layer 1351 of the tunnel junction 135 is similar to a preparation process of the n-type second doping layer 1331 of the tunnel junction 133, a preparation process of the n-type second doping layer 1351 is not repeated here, the n-type second doping layer 1351 can be obtained on the window layer 1344, similarly, a preparation process of the n-type first doping layer 1352 of the tunnel junction 135 is similar to a preparation process of the n-type first doping layer 1332 of the tunnel junction 133, the n-type first doping layer 1352 can be obtained on the n-type second doping layer 1351, a preparation process of the p-type first doping layer 1353 of the tunnel junction 135 is similar to a preparation process of the p-type first doping layer 1333 of the tunnel junction 133, and a p-type first doping layer 1353 can be obtained on the n-type first doping layer 1351, the fabrication of the p-type second doped layer 1354 of the tunnel junction 135 is similar to the fabrication of the p-type second doped layer 1334 of the tunnel junction 133, and the p-type second doped layer 1354 may be obtained on the p-type first doped layer 1353.

Fig. 13h is a schematic diagram of a top cell and a contact layer of a solar cell according to a thirteenth embodiment of the invention, and as shown in fig. 13h, a p-type GaInP is grown on a p-type second doping layer 1354 to serve as a back layer 1361 of the top cell 136, a p-type GaInP layer is grown on the back layer 1361 to serve as a base region 1362 of the top cell 136, an n-type GaInP layer is grown on the base region 1362 to serve as an emitter layer 1363 of the top cell 136, an n-type AlGaInP layer is grown on the emitter layer 1363 to serve as a window layer 1364 of the top cell 136, and an n-type GaAs layer is grown on the window layer 1364 to serve as a contact layer 137, so as to complete the preparation of the solar cell according to the embodiments of the invention.

Fig. 14 is a schematic flow chart of a method for manufacturing a solar cell according to a fourteenth embodiment of the present invention, fig. 15 is a schematic flow chart of a method for manufacturing a solar cell according to a fifteenth embodiment of the present invention, fig. 16 is a schematic flow chart of a method for manufacturing a solar cell according to a sixteenth embodiment of the present invention, and fig. 17 is a schematic flow chart of a method for manufacturing a solar cell according to a seventeenth embodiment of the present invention, as shown in fig. 14, fig. 15, fig. 16, and fig. 17, where a method for manufacturing a solar cell according to any one of the above embodiments of the present invention includes a step for manufacturing a tunnel junction as shown in fig. 14, fig. 15, fig. 16, or fig. 17.

When the substrate of the solar cell is a p-type substrate, the preparation steps of the tunnel junction as shown in fig. 14 or fig. 15 may be adopted. When the substrate of the solar cell is an n-type substrate, the preparation steps of the tunnel junction as shown in fig. 16 or fig. 17 may be adopted.

As shown in fig. 14, in the preparation step of the tunnel junction, an n-type third doped layer, an n-type fourth doped layer, and a p-type fifth doped layer are sequentially grown from bottom to top, and the specific steps are as follows:

s1401, growing an n-type third doping layer;

specifically, when the tunnel junction between two adjacent sub-cells is manufactured, an n-type third sub-cell can be grown on the adjacent lower sub-cell by introducing a Si source or a Te source through an MOCVD methodAnd (5) doping the layers. The thickness of the n-type third doping layer can be 2-5 nm, and the n-type third doping layer can be made of n-type Al_aIn_(1-a)A is more than 0.25 and less than 0.55, and the doping concentration of n-type ions of the n-type third doping layer can be 5E 17-5E 18 ions/cm³。

S1402, growing an n-type fourth doping layer on the n-type third doping layer, wherein the doping concentration of n-type ions of the n-type fourth doping layer is higher than that of the n-type ions of the n-type third doping layer;

specifically, after the n-type third doping layer is manufactured, an n-type fourth doping layer can be grown on the n-type third doping layer by introducing a Si source or a Te source through an MOCVD method, wherein the doping concentration of n-type ions of the n-type fourth doping layer is higher than that of n-type ions of the n-type third doping layer. The thickness of the n-type fourth doping layer can be 5-10 nm, and the n-type fourth doping layer can be n-type Al_bIn_(1-b)The P layer, b is more than 0.25 and less than 0.55, and the doping concentration of n-type ions of the n-type fourth doping layer can be 2E 19-2E 20 ions/cm³Since the n-type fourth doping layer needs to obtain a higher doping concentration of n-type ions, the flow rate of the introduced Si source or Te source may be increased, for example, the flow rate of the introduced Si source or Te source is 2-5 times that of the Si source or Te source introduced in step S1401.

S1403, growing a p-type fifth doping layer on the n-type fourth doping layer;

specifically, after the n-type fourth doping layer is manufactured, an Mg source or a C source may be introduced through an MOCVD method, and a p-type fifth doping layer may be grown on the n-type fourth doping layer. The thickness of the p-type fifth doping layer can be 2-5 nm, and the p-type fifth doping layer can be p-type Al_cIn_(1-c)The P layer, c is more than 0.25 and less than 0.55, and the doping concentration of P-type ions of the P-type fifth doping layer is 5E 17-5E 18 ions/cm³. And after the p-type fifth doping layer is manufactured, manufacturing an upper sub-cell adjacent to the tunneling junction.

As shown in fig. 15, in the preparation step of the tunnel junction, the p-type fifth doped layer, the n-type fourth doped layer, and the n-type third doped layer are sequentially grown from bottom to top, and the specific steps are as follows:

1501. growing an n-type fifth doping layer;

specifically, when the tunnel junction between two adjacent sub-cells is manufactured, a Si source or a Te source can be introduced through an MOCVD method, and an n-type fifth doping layer is grown on the adjacent lower sub-cell. The thickness of the n-type fifth doping layer can be 2-5 nm, and the n-type fifth doping layer can be made of n-type Al_gIn_(1-g)The P layer, g is more than 0.25 and less than 0.55, and the doping concentration of n-type ions of the n-type fifth doping layer can be 5E 17-5E 18/cm³。

1502. Growing a p-type fourth doping layer on the n-type fifth doping layer;

specifically, after the n-type fifth doping layer is manufactured, an Mg source or a C source may be introduced through an MOCVD method, and a p-type fourth doping layer may be grown on the n-type fifth doping layer. The thickness of the p-type fourth doping layer can be 5-10 nm, and the p-type fourth doping layer can be p-type Al_fIn_(1-f)The P layer, f is more than 0.25 and less than 0.55, and the doping concentration of P-type ions of the P-type fourth doping layer can be 2E 19-2E 20/cm³。

1503. And growing a p-type third doping layer on the p-type fourth doping layer, wherein the doping concentration of p-type ions of the p-type fourth doping layer is higher than that of n-type ions of the p-type third doping layer.

Specifically, after the p-type fourth doping layer is manufactured, an Mg source or a C source may be introduced through an MOCVD method, and a p-type third doping layer may be grown on the p-type fourth doping layer, where a doping concentration of p-type ions of the p-type fourth doping layer is higher than a doping concentration of p-type ions of the p-type third doping layer. The thickness of the p-type third doping layer can be 2-5 nm, and the p-type third doping layer can be p-type Al_dIn_(1-d)D is more than 0.25 and less than 0.55, and the doping concentration of P-type ions of the P-type third doping layer is 5E 17-5E 18 ions/cm³Since the p-type third doping layer needs to obtain a lower doping concentration of p-type ions,the flow rate of the Mg source or the C source introduced may be reduced, for example, the flow rate of the Mg source or the C source introduced is 50% to 80% of the flow rate of the Mg source or the C source introduced in step S1502. And after the p-type third doping layer is manufactured, manufacturing an upper layer sub-cell adjacent to the tunneling junction.

As shown in fig. 16, in the preparation step of the tunnel junction, the p-type third doped layer, the p-type fourth doped layer and the n-type fifth doped layer are sequentially grown from bottom to top, and the specific steps are as follows:

1601. growing the p-type third doping layer;

specifically, when the tunnel junction between two adjacent sub-cells is manufactured, an Mg source or a C source can be introduced through an MOCVD method, and a p-type third doping layer grows on the adjacent lower sub-cell. The thickness of the p-type third doping layer can be 2-5 nm, and the p-type third doping layer can be made of p-type Al_dIn_(1-d)The P layer, d is more than 0.25 and less than 0.55, and the doping concentration of P-type ions of the P-type third doping layer can be 5E 17-5E 18/cm³。

1602. Growing the p-type fourth doping layer on the p-type third doping layer, wherein the doping concentration of p-type ions of the p-type fourth doping layer is higher than that of the p-type ions of the p-type third doping layer;

specifically, after the p-type third doping layer is manufactured, an Mg source or a C source may be introduced through an MOCVD method, and a p-type fourth doping layer may be grown on the p-type third doping layer, where a doping concentration of p-type ions of the p-type fourth doping layer is higher than a doping concentration of p-type ions of the p-type third doping layer. The thickness of the p-type fourth doping layer can be 5-10 nm, and the p-type fourth doping layer can be p-type Al_fIn_(1-f)The P layer, f is more than 0.25 and less than 0.55, and the doping concentration of P-type ions of the P-type fourth doping layer can be 2E 19-2E 20/cm³Since the p-type fourth doping layer needs to obtain a higher doping concentration of p-type ions, the flow rate of the introduced Mg source or C source may be increased, for example, the flow rate of the introduced Mg source or C source is 2-5 times that of the Mg source or C source introduced in step S1601.

1603. Growing the n-type fifth doping layer on the p-type fourth doping layer;

specifically, after the p-type fourth doping layer is manufactured, a Si source or a Te source may be introduced through an MOCVD method, and the n-type fifth doping layer may be grown on the p-type fourth doping layer. The thickness of the n-type fifth doping layer can be 5-10 nm, and the n-type fifth doping layer can be Al_gIn_(1-g)The P layer, g is more than 0.25 and less than 0.55, the doping concentration of n-type ions of the n-type fifth doping layer can be 2E 19-2E 20 ions/cm³。

As shown in fig. 17, in the preparation step of the tunnel junction, the p-type fifth doped layer, the n-type fourth doped layer, and the n-type third doped layer are sequentially grown from bottom to top, and the specific steps are as follows:

1701. growing a p-type fifth doping layer;

specifically, when the tunnel junction between two adjacent sub-cells is manufactured, an Mg source or a C source can be introduced through an MOCVD method, and a p-type fifth doping layer grows on the adjacent lower sub-cell. The thickness of the p-type fifth doping layer can be 2-5 nm, and the p-type fifth doping layer can be made of p-type Al_cIn_(1-c)The P layer, c is more than 0.25 and less than 0.55, and the doping concentration of P-type ions of the P-type fifth doping layer can be 5E 17-5E 18/cm³。

1702. Growing an n-type fourth doping layer on the p-type fifth doping layer;

specifically, after the p-type fifth doping layer is manufactured, a Si source or a Te source may be introduced through an MOCVD method, and the n-type fourth doping layer may be grown on the p-type fifth doping layer. The thickness of the n-type fourth doping layer can be 5-10 nm, and the n-type fourth doping layer can be Al_bIn_(1-b)The P layer, b is more than 0.25 and less than 0.55, and the doping concentration of n-type ions of the n-type fourth doping layer can be 2E 19-2E 20 ions/cm³。

1703. Growing an n-type third doping layer on the n-type fourth doping layer, wherein the doping concentration of n-type ions of the n-type fourth doping layer is higher than that of the n-type ions of the n-type third doping layer;

specifically, after the n-type fourth doping layer is manufactured, an n-type third doping layer can be grown on the n-type fourth doping layer by introducing a Si source or a Te source through an MOCVD method, wherein the doping concentration of n-type ions of the n-type fourth doping layer is higher than that of n-type ions of the n-type third doping layer. The thickness of the n-type third doping layer can be 2-5 nm, and the n-type third doping layer can be n-type Al_aIn_(1-a)A is more than 0.25 and less than 0.55, and the doping concentration of n-type ions of the n-type third doping layer is 5E 17-5E 18 ions/cm³Since the n-type third doping layer needs to obtain a lower doping concentration of n-type ions, the flow rate of the introduced Si source or Te source may be reduced, for example, the flow rate of the introduced Si source or Te source is 50% to 80% of the flow rate of the introduced Si source or Te source in step S1702. And after the n-type third doping layer is manufactured, manufacturing an upper layer sub-cell adjacent to the tunneling junction.

It can be understood that the specific processes for preparing the substrate, each segment cell and the contact layer of the solar cell are the prior art and are not described herein.

In addition to the above embodiments, in the method for manufacturing a solar cell according to the embodiments of the present invention, the growth temperature conditions of the n-type third doped layer and the p-type fifth doped layer are 500 to 650 degrees celsius, and the growth temperature condition of the n-type fourth doped layer is 700 to 830 degrees celsius.

Specifically, the temperature of the MOCVD reaction chamber can be set to be 500-650 ℃ when growing the n-type third doping layer or the p-type fifth doping layer, so as to meet the growth temperature condition of the n-type third doping layer or the p-type fifth doping layer, and the growth temperature of the n-type third doping layer or the p-type fifth doping layer is set to be 500-650 ℃, which is beneficial to obtaining higher doping concentration. When the n-type fourth doping layer is grown, the temperature of an MOCVD reaction chamber can be set to be 700-830 ℃ so as to meet the growth temperature condition of the n-type fourth doping layer, and the n-type fourth doping layer is set to be 700-830 ℃, so that the n-type fourth doping layer with good crystal quality can be obtained.

On the basis of the above embodiments, in the method for manufacturing a solar cell according to the embodiments of the present invention, the growth rate of the n-type fourth doped layer is 0.5 to 2nm/s, the growth rate of the n-type third doped layer is 0.2 to 1nm/s, and the growth rate of the p-type fifth doped layer is 0.2 to 1 nm/s. And limiting the growth rate of the n-type fourth doping layer to 0.5-2 nm/s, so that the production efficiency is ensured and the product quality of the n-type fourth doping layer is ensured. Limiting the growth rate of the n-type third doping layer and the growth rate of the p-type fifth doping layer to 0.2-1 nm/s, and ensuring the production efficiency and the product quality of the n-type third doping layer and the p-type fifth doping layer.

In addition to the above embodiments, in the method for manufacturing a solar cell according to the embodiments of the present invention, the growth temperature conditions of the p-type third doped layer and the n-type fifth doped layer are 500 to 650 degrees celsius, and the growth temperature condition of the p-type fourth doped layer is 700 to 830 degrees celsius.

Specifically, the temperature of the MOCVD reaction chamber can be set to be 500-650 ℃ when growing the p-type third doping layer or the n-type fifth doping layer, so as to meet the growth temperature condition of the p-type third doping layer or the n-type fifth doping layer, and the growth temperature of the p-type third doping layer or the n-type fifth doping layer is set to be 500-650 ℃, which is beneficial to obtaining higher doping concentration. When the p-type fourth doping layer grows, the temperature of an MOCVD reaction chamber can be set to be 700-830 ℃ so as to meet the growth temperature condition of the p-type fourth doping layer, and the p-type fourth doping layer is set to be 700-830 ℃, so that the p-type fourth doping layer with good crystal quality can be obtained.

On the basis of the above embodiments, in the method for manufacturing a solar cell according to the embodiments of the present invention, the growth rate of the p-type fourth doped layer is 0.5 to 2nm/s, the growth rate of the p-type third doped layer is 0.2 to 1nm/s, and the growth rate of the n-type fifth doped layer is 0.2 to 1 nm/s. And limiting the growth rate of the p-type fourth doping layer to 0.5-2 nm/s, so that the production efficiency is ensured, and the product quality of the p-type fourth doping layer is ensured. Limiting the growth rate of the p-type third doping layer and the growth rate of the n-type fifth doping layer to 0.2-1 nm/s, and ensuring the product quality of the p-type third doping layer and the n-type fifth doping layer while ensuring the production efficiency.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.