阅读说明：本技术 一种可变光谱GaAlAs光电发射材料及其制备方法 (Variable spectrum GaAlAs photoelectric emission material and preparation method thereof ) 是由 徐源 于 2021-01-27 设计创作，主要内容包括：本发明公开了一种可变光谱GaAlAs光电发射材料及其制备方法,它包括衬底,衬底的上表面生长有掺杂的AlN缓冲层,AlN缓冲层的上表面生长p型指数掺杂GaAlAs光电发射层,p型指数掺杂GaAlAs光电发射层的上表面吸附单层Cs或多层Cs/O,以形成Cs或Cs/O激活层。该结构采用梯度掺杂光电发射层,增大了发射层内光激发电子的逃逸深度,提高了发射层内电子发射到真空的几率,从而提高了GaAlAs可变光谱技术的总体量子效率,获得较高的紫外灵敏度。(The invention discloses a variable spectrum GaAlAs photoelectric emission material and a preparation method thereof, and the variable spectrum GaAlAs photoelectric emission material comprises a substrate, wherein a doped AlN buffer layer is grown on the upper surface of the substrate, a p-type exponential doped GaAlAs photoelectric emission layer is grown on the upper surface of the AlN buffer layer, and the upper surface of the p-type exponential doped GaAlAs photoelectric emission layer adsorbs single-layer Cs or multiple layers of Cs/O to form a Cs or Cs/O activation layer. The structure adopts the gradient doped photoelectric emission layer, increases the escape depth of photoexcited electrons in the emission layer, and improves the probability of electron emission to vacuum in the emission layer, thereby improving the overall quantum efficiency of the GaAlAs variable spectrum technology and obtaining higher ultraviolet sensitivity.)

1. A variable-spectrum GaAlAs photoelectric emission material is characterized in that: the solar cell comprises a substrate, wherein a doped AlN buffer layer is grown on the upper surface of the substrate, a p-type exponential-doped GaAlAs photoelectric emission layer is grown on the upper surface of the AlN buffer layer, and a single-layer Cs or multi-layer Cs/O is adsorbed on the upper surface of the p-type exponential-doped GaAlAs photoelectric emission layer to form a Cs or Cs/O activation layer.

2. The variable spectrum GaAlAs photoemissive material of claim 1, wherein: the AlN buffer layer is 50-100nm thick, and the p-type index doped GaAlAs photoelectric emission layer is 120-180nm thick.

3. The method of claim 1, wherein the method comprises the steps of:

step 1, growing a doped AlN buffer layer on the upper surface of a substrate with two polished surfaces by an epitaxial growth process of a semiconductor material;

step 2, growing a p-type index doped GaAlAs photoelectric emission layer on the AlN buffer layer obtained in the step 1 as a photoelectric emission material through an epitaxial growth process and a p-type doping process of a III-V group compound semiconductor material;

step 3, removing the grease on the surface of the cathode material obtained in the step 2 and the residual inorganic attachments in the processing process by utilizing chemical cleaning; then the material is sent into an ultrahigh vacuum system, and the surface of the material is heated and purified to reach the atomic level cleanness;

and 4, adsorbing a single-layer Cs or a plurality of layers of Cs/O on the surface of the p-type GaAlAs photoelectric emission layer material through an activation process to form a Cs or Cs/O activation layer, and finally preparing the variable spectrum GaAlAs photoelectric emission material.

4. The method of claim 3, wherein the method comprises the steps of: the thickness of the p-type index-doped GaAlAs photoelectric emission layer in the step 2 is 120-180nm, and the doping concentration range is 1016-1019cm^-3And the doping concentration is reduced from the inside to the surface in turn according to an exponential law; the vacuum degree in the ultrahigh vacuum system in the step 3 reaches or is superior to 10^-8Pa magnitude, 780-830 ℃ of temperature when the surface of the material is heated and purified, and 10-30min of heating time.

Technical Field

The invention belongs to the technical field of detection materials, and particularly relates to a variable spectrum GaAlAs photoelectric emission material and a preparation method thereof.

Background

In recent years, along with the perfection of GaAlAs material preparation technology, p-type doping technology and the development of ultrahigh vacuum technology. The GaAlAs variable spectrum photocathode can work in a reflection mode or a transmission mode, and the GaAlAs variable spectrum material is doped uniformly in a p-type mode, so that concentration difference exists between the surface of an emitting layer and the inside of the emitting layer, and electrons excited to a conduction band by incident light move to the body surface in a diffusion mode. In the transport process, some electrons are compounded after losing energy after colliding with crystal lattices for many times and cannot escape, so that the emission quantity of the electrons is reduced, and the quantum efficiency of the cathode is low.

The research of the literature finds that the adoption of the gradient doped structure photoelectric emission layer can improve the transport capacity of photoexcited electrons from the inside of the body to the surface of the body, increase the electron escape amount and further obtain higher quantum efficiency. The photoelectric emission layer adopts a proper gradient doping structure, a built-in electric field which is beneficial to the movement of electrons to the surface can be generated in the emission layer body, so that the electrons excited to a conduction band have diffusion movement caused by concentration difference between the inside and the outside of the body in the process of moving to the surface, and can also make drift movement under the action of the built-in electric field, the movement mode of diffusion and drift can increase the probability of the electrons reaching the surface of the cathode, further the escape probability of the electrons is increased, and the quantum efficiency is improved. However, the adoption of the gradient doping structure has the defects that the theoretical support is relatively weak, no proper method is used for calculating the concentration and the thickness of each layer, and the theoretical simulation and the data optimization are not convenient.

Disclosure of Invention

The invention provides a variable spectrum GaAlAs photoelectric emission material and a preparation method thereof, and the material with the structure improves the escape probability of photoexcited electrons of an emission layer on one hand and is convenient for theoretical design, theoretical simulation and data optimization on the other hand. When the electrons are emitted to vacuum, the electrons are collected by external strong voltage and are output in a photocurrent mode through an external acquisition circuit, so that the sensitivity of the visible spectrum is improved.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a variable spectrum GaAlAs photoelectric emission material, which comprises a substrate, wherein a doped AlN buffer layer is grown on the upper surface of the substrate, a p-type index-doped GaAlAs photoelectric emission layer is grown on the upper surface of the AlN buffer layer, and a single-layer Cs or multi-layer Cs/O is adsorbed on the upper surface of the p-type index-doped GaAlAs photoelectric emission layer to form a Cs or Cs/O activation layer.

As the above-mentioned variable spectrum GaAlAs photoelectric emission material, the thickness of the AlN buffer layer is 50-100nm, and the thickness of the p-type index doping GaAlAs photoelectric emission layer is 120-180 nm.

The preparation method of the variable spectrum GaAlAs photoelectric emission material comprises the following steps:

step 1, growing a doped AlN buffer layer on the upper surface of a substrate with two polished surfaces by an epitaxial growth process of a semiconductor material; step 2, growing a p-type index doped GaAlAs photoelectric emission layer on the AlN buffer layer obtained in the step 1 as a photoelectric emission material through an epitaxial growth process and a p-type doping process of a III-V group compound semiconductor material; step 3, removing the grease on the surface of the cathode material obtained in the step 2 and the residual inorganic attachments in the processing process by utilizing chemical cleaning; then the material is sent into an ultrahigh vacuum system, and the surface of the material is heated and purified to reach the atomic level cleanness; and 4, adsorbing a single-layer Cs or a plurality of layers of Cs/O on the surface of the p-type GaAlAs photoelectric emission layer material through an activation process to form a Cs or Cs/O activation layer, and finally preparing the variable spectrum GaAlAs photoelectric emission material.

In the preparation method of the above-mentioned variable spectrum GaAlAs photoelectric emission material, the thickness of the p-type index doped GaAlAs photoelectric emission layer in step 2 is 120-180nm, and the doping concentration range is 1016-1019cm^-3And the doping concentration is reduced from the inside to the surface in turn according to an exponential law; the vacuum degree in the ultrahigh vacuum system in the step 3 reaches or is superior to 10^-8Pa magnitude, 780-830 ℃ of temperature when the surface of the material is heated and purified, and 10-30min of heating time.

Compared with the existing degradable magnesium alloy biomedical material, the invention has the advantages that:

the material of the structure of the invention improves the escape probability of the photoexcited electrons of the emitting layer on one hand, and is convenient for theoretical design, theoretical simulation and data optimization on the other hand. When the electrons are emitted to vacuum, the electrons are collected by external strong voltage and are output in a photocurrent mode through an external acquisition circuit, so that the sensitivity of the visible spectrum is improved.

The specific implementation mode is as follows:

the invention is further illustrated by the following examples:

example 1

The invention provides a variable spectrum GaAlAs photoelectric emission material, which comprises a substrate and a substrate sapphire material, wherein a doped AlN buffer layer is grown on the upper surface of the substrate, a p-type index-doped GaAlAs photoelectric emission layer is grown on the upper surface of the AlN buffer layer, and the upper surface of the p-type index-doped GaAlAs photoelectric emission layer adsorbs single-layer Cs or multiple layers of Cs/O to form a Cs or Cs/O activation layer; the AlN buffer layer is 50nm thick, and the p-type exponential doping GaAlAs photoelectric emission layer is 160nm thick.

The preparation method of the variable spectrum GaAlAs photoelectric emission material comprises the following steps:

step 1, growing a doped AlN buffer layer on the upper surface of a substrate with two polished surfaces by an epitaxial growth process of a semiconductor material; step 2, growing a p-type index doped GaAlAs photoelectric emission layer on the AlN buffer layer obtained in the step 1 as a photoelectric emission material through an epitaxial growth process and a p-type doping process of a III-V group compound semiconductor material; the thickness of the p-type index-doped GaAlAs photoelectric emission layer is 160nm, and the doping concentration range is 1018-1019cm^-3And the doping concentration is reduced from the inside to the surface in turn according to an exponential law; step 3, removing the grease on the surface of the cathode material obtained in the step 2 and the residual inorganic attachments in the processing process by utilizing chemical cleaning; then the material is sent into an ultrahigh vacuum system, and the surface of the material is heated and purified to reach the atomic level cleanness; the vacuum degree in the ultra-high vacuum system reaches or is superior to 10^-8Pa magnitude, the temperature when the surface of the material is heated and purified is 790 ℃, and the heating time is 20 min; and 4, adsorbing a single-layer Cs or a plurality of layers of Cs/O on the surface of the p-type GaAlAs photoelectric emission layer material through an activation process to form a Cs or Cs/O activation layer, and finally preparing the variable spectrum GaAlAs photoelectric emission material.

Example 2

A variable spectrum GaAlAs photoelectric emission material comprises a substrate and a substrate sapphire material, wherein a doped AlN buffer layer is grown on the upper surface of the substrate, a p-type index-doped GaAlAs photoelectric emission layer is grown on the upper surface of the AlN buffer layer, and the upper surface of the p-type index-doped GaAlAs photoelectric emission layer adsorbs single-layer Cs or multi-layer Cs/O to form a Cs or Cs/O activation layer; the AlN buffer layer is 90nm thick, and the p-type index-doped GaAlAs photoelectric emission layer is 140nm thick.

The preparation method of the variable spectrum GaAlAs photoelectric emission material comprises the following steps:

step 1, growing a doped AlN buffer layer on the upper surface of a substrate with two polished surfaces by an epitaxial growth process of a semiconductor material; step 2, growing p-type exponential-doped GaAlAs photoelectric generator on the AlN buffer layer obtained in the step 1 through epitaxial growth process and p-type doping process of III-V group compound semiconductor materialThe emitting layer is used as a photoelectric emitting material; the thickness of the p-type index-doped GaAlAs photoelectric emission layer is 140nm, and the doping concentration range is 1016-1019cm^-3And the doping concentration is reduced from the inside to the surface in turn according to an exponential law; step 3, removing the grease on the surface of the cathode material obtained in the step 2 and the residual inorganic attachments in the processing process by utilizing chemical cleaning; then the material is sent into an ultrahigh vacuum system, and the surface of the material is heated and purified to reach the atomic level cleanness; the vacuum degree in the ultra-high vacuum system reaches or is superior to 10^-8Pa magnitude, the temperature when the surface of the material is heated and purified is 800 ℃, and the heating time is 25 min; and 4, adsorbing a single-layer Cs or a plurality of layers of Cs/O on the surface of the p-type GaAlAs photoelectric emission layer material through an activation process to form a Cs or Cs/O activation layer, and finally preparing the variable spectrum GaAlAs photoelectric emission material.

Example 3

A variable spectrum GaAlAs photoelectric emission material comprises a substrate and a substrate sapphire material, wherein a doped AlN buffer layer is grown on the upper surface of the substrate, a p-type index-doped GaAlAs photoelectric emission layer is grown on the upper surface of the AlN buffer layer, and the upper surface of the p-type index-doped GaAlAs photoelectric emission layer adsorbs single-layer Cs or multi-layer Cs/O to form a Cs or Cs/O activation layer; the AlN buffer layer is 50nm thick, and the p-type index-doped GaAlAs photoelectric emission layer is 180nm thick.

The preparation method of the variable spectrum GaAlAs photoelectric emission material comprises the following steps:

step 1, growing a doped AlN buffer layer on the upper surface of a substrate with two polished surfaces by an epitaxial growth process of a semiconductor material; step 2, growing a p-type index doped GaAlAs photoelectric emission layer on the AlN buffer layer obtained in the step 1 as a photoelectric emission material through an epitaxial growth process and a p-type doping process of a III-V group compound semiconductor material; the thickness of the p-type index doped GaAlAs photoelectric emission layer is 180nm, and the doping concentration range is 1017-^-3And the doping concentration is reduced from the inside to the surface in turn according to an exponential law; step 3, removing the grease on the surface of the cathode material obtained in the step 2 and the residual inorganic attachments in the processing process by utilizing chemical cleaning; then put it inSending the material into an ultrahigh vacuum system, and heating and purifying the surface of the material to ensure that the surface of the material reaches the atomic-level cleanliness; the vacuum degree in the ultra-high vacuum system reaches or is superior to 10^-8Pa magnitude, the temperature for heating and purifying the surface of the material is 780 ℃, and the heating time is 30 min; and 4, adsorbing a single-layer Cs or a plurality of layers of Cs/O on the surface of the p-type GaAlAs photoelectric emission layer material through an activation process to form a Cs or Cs/O activation layer, and finally preparing the variable spectrum GaAlAs photoelectric emission material.

Example 4

A variable spectrum GaAlAs photoelectric emission material comprises a substrate and a substrate sapphire material, wherein a doped AlN buffer layer is grown on the upper surface of the substrate, a p-type index-doped GaAlAs photoelectric emission layer is grown on the upper surface of the AlN buffer layer, and the upper surface of the p-type index-doped GaAlAs photoelectric emission layer adsorbs single-layer Cs or multi-layer Cs/O to form a Cs or Cs/O activation layer; the AlN buffer layer is 100nm thick, and the p-type exponential-doped GaAlAs photoelectric emission layer is 120nm thick.

The preparation method of the variable spectrum GaAlAs photoelectric emission material comprises the following steps:

step 1, growing a doped AlN buffer layer on the upper surface of a substrate with two polished surfaces by an epitaxial growth process of a semiconductor material; step 2, growing a p-type index doped GaAlAs photoelectric emission layer on the AlN buffer layer obtained in the step 1 as a photoelectric emission material through an epitaxial growth process and a p-type doping process of a III-V group compound semiconductor material; the thickness of the p-type index-doped GaAlAs photoelectric emission layer is 120nm, and the doping concentration range is 1018-1019cm^-3And the doping concentration is reduced from the inside to the surface in turn according to an exponential law; step 3, removing the grease on the surface of the cathode material obtained in the step 2 and the residual inorganic attachments in the processing process by utilizing chemical cleaning; then the material is sent into an ultrahigh vacuum system, and the surface of the material is heated and purified to reach the atomic level cleanness; the vacuum degree in the ultra-high vacuum system reaches or is superior to 10^-8Pa magnitude, the temperature for heating and purifying the surface of the material is 830 ℃, and the heating time is 10 min; step 4, exciting the surface of the p-type GaAlAs photoelectric emission layer materialAnd adsorbing single-layer Cs or multi-layer Cs/O by using an active process to form a Cs or Cs/O active layer, and finally preparing the variable-spectrum GaAlAs photoelectric emission material.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The above-described embodiments of the invention are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, and not by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.