阅读说明：本技术 一种量子点微激光器及其制备方法 (Quantum dot micro laser and preparation method thereof ) 是由 朱刚毅 叶鹏 秦飞飞 严星灿 于 2021-07-27 设计创作，主要内容包括：本发明公开了一种量子点微激光器及其制备方法,激光器采用悬浮硅盘结构,悬浮硅盘结构包括从下到上依次设置的硅衬底层、第一二氧化硅层、二氧化硅支柱层和二氧化硅圆盘层,在二氧化硅圆盘层上表面悬涂有量子点层,在量子点层上覆盖有第二二氧化硅层；所述制备方法采用光刻刻蚀工艺和RIE刻蚀工艺制备悬浮硅盘结构的微腔,使其在高温中退火后悬涂不同尺寸的量子点,并蒸镀二氧化硅。本发明激光器能够获得白光激光,具有极高的光学增益和极低的损耗,有利于与光电子器件集成,可以获得高光转换效率低阈值。(The invention discloses a quantum dot micro laser and a preparation method thereof, wherein the laser adopts a suspended silicon disk structure, the suspended silicon disk structure comprises a silicon substrate layer, a first silicon dioxide layer, a silicon dioxide strut layer and a silicon dioxide disk layer which are sequentially arranged from bottom to top, a quantum dot layer is suspended on the upper surface of the silicon dioxide disk layer, and a second silicon dioxide layer covers the quantum dot layer; the preparation method adopts a photoetching process and an RIE (reactive ion etching) process to prepare the microcavity with the suspended silicon disk structure, enables the microcavity to be coated with quantum dots with different sizes in a suspended mode after annealing at high temperature, and evaporates and coats silicon dioxide. The laser can obtain white light laser, has extremely high optical gain and extremely low loss, is favorable for being integrated with a photoelectronic device, and can obtain high light conversion efficiency and low threshold value.)

1. The quantum dot micro laser is characterized in that the quantum dot micro laser adopts a suspended silicon disc structure, the suspended silicon disc structure comprises a silicon substrate layer (1), a first silicon dioxide layer (2), a silicon dioxide strut layer (3) and a silicon dioxide disc layer (4) which are sequentially arranged from bottom to top, a quantum dot layer (5) is suspended on the upper surface of the silicon dioxide disc layer (4), and a second silicon dioxide layer (6) covers the quantum dot layer (5); a plurality of quantum dots of different sizes are provided on the quantum dot layer (5).

2. A quantum dot micro-laser according to claim 1, characterized in that the suspended silicon disk structure comprises at least 3 silica pillar layers (3), each silica pillar layer (3) supporting one silica disk layer (4).

3. A quantum dot micro laser as claimed in claim 1, characterized in that 3 different sizes of quantum dots of the same material are arranged on the quantum dot layer (5).

4. A quantum dot micro-laser according to claim 3, characterized in that the quantum dots on the quantum dot layer (5) have sizes of 410nm, 545nm and 660nm, respectively.

5. A quantum dot micro-laser as claimed in claim 3, wherein the material of the quantum dot is CdTe.

6. The quantum dot micro-laser as claimed in claim 1, wherein the silica support layer (3) is fabricated by suspending a buffered oxide etching solution.

7. A quantum dot micro-laser according to claim 1, characterized in that the second silicon dioxide layer (6) is made by magnetron sputter evaporation.

8. A preparation method of a quantum dot micro laser is characterized in that the quantum dot micro laser adopts the quantum dot micro laser as claimed in any one of claims 1 to 7, and the preparation method comprises the following steps:

s1, spin-coating photoresist on the upper surface of the SOI wafer, and defining a disc micro-cavity structure on the photoresist layer by utilizing an optical lithography technology;

s2, etching the photoresist mask on the SOI wafer by using a reactive ion etching technology based on the disc micro-cavity structure to obtain the SOI wafer containing the silicon disc structure;

s3, suspending the SOI wafer containing the silicon disc structure by using the buffer oxide etching liquid to generate a silicon strut for supporting the silicon disc structure, and further obtaining the SOI wafer containing the suspension silicon disc;

s4, annealing the SOI wafer containing the suspension silicon disk in the air to obtain a suspension silicon disk structure consisting of a silicon substrate layer (1), a first silicon dioxide layer (2), a silicon dioxide strut layer (3) and a silicon dioxide disk layer (4);

s5, coating a plurality of quantum dots with different sizes on the silicon dioxide disc layer (4) in a suspension mode to obtain a quantum dot layer (5);

and S6, evaporating a layer of silicon dioxide on the quantum dot layer (5) by utilizing a magnetron sputtering technology to obtain a second silicon dioxide layer (6).

9. The method of claim 8, wherein in step S3, the SOI wafer containing the silicon disk structure is immersed in a mixed solution of hydrofluoric acid and fluorinated ammonia, and then suspended.

Technical Field

The invention relates to a quantum dot micro laser and a preparation method thereof, belonging to the technical field of laser.

Background

The semiconductor quantum dot material is a novel semiconductor material which is artificially designed and manufactured, the motion of a current carrier in three spatial directions is restricted, the semiconductor quantum dot material has a strong three-dimensional quantum confinement effect, the obvious effects of quantum tunneling, quantum interference, coulomb blockage, nonlinear optics and the like are reflected, the semiconductor quantum dot material is a physical basis of a new generation of solid-state quantum devices, and the semiconductor quantum dot material has extremely important application prospects in the aspects of nanoelectronics, optoelectronics, a new generation of super-large-scale integrated circuits and the like.

At present, utilize the quantum dot laser source of a material to realize white light laser, in white light laser conversion process, most laser energy is converted into broad spectrum light, luminous angle obviously increases, can improve its security, more be applicable to some civilian occasions, and the cost is lower, combine quantum dot and microcavity structure, can further improve quantum dot laser's optical property, but the microcavity structure surface smoothness degree of this type of quantum dot laser at present is not enough, and the structural design of microcavity also exists inadequately, lead to the laser loss great, quantum dot luminous efficiency is lower.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a quantum dot micro laser and a preparation method thereof.

In order to solve the technical problems, the invention adopts the following technical means:

in a first aspect, the invention provides a quantum dot micro laser, which adopts a suspended silicon disk structure, wherein the suspended silicon disk structure comprises a silicon substrate layer, a first silicon dioxide layer, a silicon dioxide strut layer and a silicon dioxide disk layer which are sequentially arranged from bottom to top, a quantum dot layer is suspended on the upper surface of the silicon dioxide disk layer, and a second silicon dioxide layer covers the quantum dot layer; a plurality of quantum dots of different sizes are disposed on the quantum dot layer.

With reference to the first aspect, further, the suspended silicon disk structure includes at least 3 silica pillar layers, each supporting one silica disk layer.

In combination with the first aspect, further, quantum dots of 3 different sizes and the same material are disposed on the quantum dot layer.

In combination with the first aspect, further, the quantum dots on the quantum dot layer have sizes of 410nm, 545nm, and 660nm, respectively.

In combination with the first aspect, further, the material of the quantum dots is CdTe.

With reference to the first aspect, further, the silica support layer is formed by suspending a buffered oxide etching solution.

With reference to the first aspect, the second silicon dioxide layer is further formed by magnetron sputtering evaporation.

In a second aspect, the present invention provides a method for preparing a quantum dot micro laser, where the quantum dot micro laser according to the first aspect of the present invention is used, and the method includes the following steps:

s1, spin-coating photoresist on the upper surface of the SOI wafer, and defining a disc micro-cavity structure on the photoresist layer by utilizing an optical lithography technology;

s2, etching the photoresist mask on the SOI wafer by using a reactive ion etching technology based on the disc micro-cavity structure to obtain the SOI wafer containing the silicon disc structure;

s3, suspending the SOI wafer containing the silicon disc structure by using the buffer oxide etching liquid to generate a silicon strut for supporting the silicon disc structure, and further obtaining the SOI wafer containing the suspension silicon disc;

s4, annealing the SOI wafer containing the suspension silicon disk in the air to obtain a suspension silicon disk structure consisting of a silicon substrate layer, a first silicon dioxide layer, a silicon dioxide strut layer and a silicon dioxide disk layer;

s5, coating a plurality of quantum dots with different sizes on the silicon dioxide disc layer (4) in a suspension mode to obtain a quantum dot layer (5);

and S6, evaporating a layer of silicon dioxide on the quantum dot layer (5) by utilizing a magnetron sputtering technology to obtain a second silicon dioxide layer (6).

In combination with the second aspect, further, in step S3, the SOI wafer including the silicon disk structure is immersed in a mixed solution of hydrofluoric acid and fluorinated ammonia, and then subjected to a suspension process.

The following advantages can be obtained by adopting the technical means:

the invention provides a quantum dot micro laser and a preparation method thereof, the quantum dot micro laser takes an SOI wafer of a silicon substrate as a carrier to prepare a suspended silicon disk structure, a quantum layer containing 3 kinds of size quantum dots is arranged on the suspended silicon disk structure, after stimulated radiation, the 3 kinds of size quantum dots emit light in three wave bands of red, green and blue, and finally white light laser is realized through a suspended disk micro-cavity. The suspended silicon disc structure of the invention utilizes the silicon dioxide support column layer to separate the silicon layer and the silicon dioxide disc layer to a greater extent, and can effectively reduce loss, thereby improving the luminous efficiency of the quantum dot disc microcavity. The preparation method of the invention utilizes the optical lithography and RIE etching as well as the hydrofluoric acid and ammonia fluoride mixed solution to corrode the silicon dioxide to prepare the micro-cavity of the suspended silicon disk structure, can obtain the suspended silicon disk structure which is supported by a column and has smooth edge, and reduces the bending loss of the structure and the scattering loss caused by rough side surface.

The quantum dot micro-laser has extremely high optical gain and extremely low loss, is favorable for being integrated with optoelectronic devices, can obtain high light conversion efficiency and low threshold value, and has good manufacturability and high processing precision.

Drawings

FIG. 1 is a side view of a quantum dot micro laser of the present invention;

FIG. 2 is a top view of a quantum dot micro laser according to the present invention;

FIG. 3 is a flow chart of the steps of a method for manufacturing a quantum dot micro laser according to the present invention;

FIG. 4 is a process flow diagram of a preparation method in an embodiment of the invention;

in the figure, 1 is a silicon substrate layer, 2 is a first silicon dioxide layer, 3 is a silicon dioxide pillar layer, 4 is a silicon dioxide disk layer, 5 is a quantum dot layer, and 6 is a second silicon dioxide layer.

Detailed Description

The technical scheme of the invention is further explained by combining the accompanying drawings as follows:

the invention provides a quantum dot micro laser, as shown in fig. 1 and 2, the quantum dot micro laser takes an SOI wafer of a silicon substrate as a carrier and adopts a suspended silicon disk structure. The suspension silicon disk structure of quantum dot micro laser includes silicon substrate layer 1, first silicon dioxide layer 2, silica pillar layer 3 and silica disc layer 4 that from the bottom up set gradually, and the upper surface on silica disc layer 4 hangs and scribbles quantum dot layer 5, is provided with a plurality of quantum dots of different sizes on quantum dot layer 5, and it has second silicon dioxide layer 6 to cover on quantum dot layer 5.

In the embodiment of the invention, the suspended silicon disk structure comprises 3 silicon dioxide strut layers 3, each silicon dioxide strut layer 3 supports one silicon dioxide disk layer 4, and the silicon dioxide strut layers 3 are manufactured by suspending buffer oxide etching liquid (BOE).

The first silicon dioxide layer 2 and the silicon dioxide disc layer 4 are made by annealing silicon at high temperature, and the second silicon dioxide layer 6 is made by magnetron sputtering evaporation.

The quantum dot layer 5 of the quantum dot micro laser is provided with 3 kinds of quantum dots with different sizes and the same material, the quantum dot material is CdTe, the sizes of the quantum dots are respectively 410nm, 545nm and 660nm, after the quantum dots are subjected to stimulated radiation, the quantum dots with 3 sizes emit light in three wave bands of red, green and blue, and finally white light laser is realized through a suspended disc microcavity.

The invention also provides a preparation method of the quantum dot micro laser, which takes the preparation of the quantum dot micro laser with a suspended silicon disk structure, wherein the silicon substrate is 700um, the top layer silicon is 220nm thick, and the silicon dioxide is 2um thick as an example, as shown in fig. 3 and 4, the preparation method specifically comprises the following steps:

s1, obtaining the SOI wafer, sequentially ultrasonically cleaning the SOI wafer by using acetone, absolute ethyl alcohol and deionized water, and then drying the SOI wafer by using nitrogen; spin-coating photoresist AZ-5214 on the upper surface of the cleaned and blow-dried SOI wafer at the rotating speed of 4000 revolutions per minute by using a spin coater, wherein the spin-coating time is 40s (the thickness of the photoresist is 1.5 microns), and then defining a disc microcavity structure on the photoresist layer by using an optical lithography technology.

And S2, based on the disc microcavity structure, etching the SOI wafer downwards by using the Reactive Ion Etching (RIE) technology with the photoresist as a mask and the etching depth of 240nm, so that 3 disc structures are formed on the surface of the SOI wafer, and the SOI wafer containing the silicon disc structure is obtained.

S3, putting the SOI wafer containing the silicon disc structure into a prepared mixed solution of hydrofluoric acid and fluorinated ammonia water, wherein the volume ratio of the hydrofluoric acid to the fluorinated ammonia water is 1: and 6, carrying out suspension treatment on the SOI wafer containing the silicon disc structure by using BOE solution, wherein the suspension time is 30s, a silicon support column for supporting the silicon disc structure is generated, the height of the silicon support column is 2um, and the SOI wafer containing the suspension silicon disc is obtained. The refractive index of silicon is 3.42, the refractive index of silicon dioxide is 1.45, and because light has the characteristic of tending to propagate in a medium with a large refractive index, the silicon dioxide strut layer 3 designed by the invention utilizes the silicon dioxide strut layer 3 to support the silicon dioxide disc layer 4, so that the silicon layer and the silicon dioxide disc layer can be separated to a greater extent, the loss is reduced, and the luminous efficiency of the quantum dot disc microcavity is improved.

S4, performing high-temperature annealing treatment on the SOI wafer including the floating silicon disk in the air to convert most of the silicon layer on the SOI wafer into a silicon dioxide layer, specifically, converting the floating silicon disk on the SOI wafer into a silicon dioxide disk layer 4, converting the silicon pillar on the SOI wafer into a silicon dioxide pillar layer 3, converting the silicon layer below the silicon pillar into a first silicon dioxide layer 2, and obtaining the suspended silicon disk structure with the silicon layer at the bottom of the SOI wafer being a silicon substrate layer 1.

S5, a plurality of quantum dots of different sizes are suspended on the silicon dioxide disk layer 4 to obtain a quantum dot layer 5. In the embodiment of the invention, the material of the quantum dots is CdTe, and the sizes of the quantum dots are 410nm, 545nm and 660nm respectively. Because the quantum dots are small in size, the suspension coating method is adopted, the suspension coating is simple, high-quality low-threshold laser is easy to obtain, and in addition, the suspension silicon disk micro-cavity is designed and prepared by utilizing the advanced micro-nano processing technology.

And S6, evaporating a layer of silicon dioxide with the thickness of 100nm on the quantum dot layer 5 by utilizing a magnetron sputtering technology to obtain a second silicon dioxide layer 6, and thus, completing the manufacture of the quantum dot micro laser.

Compared with the traditional quantum well laser (quantum wire laser), the quantum dot laser has a discrete state density function, so that the quantum dot laser has more excellent performance. The quantum dot micro laser provided by the invention designs a suspended silicon disk structure, and utilizes the silicon dioxide support column layer to separate the silicon layer and the silicon dioxide disk layer to a greater extent, so that the loss can be reduced, the luminous efficiency of the quantum dot disk microcavity is improved, and the quantum dot micro laser has the advantages of lower threshold current density, higher threshold current temperature stability, higher differential gain, higher modulation bandwidth, insensitivity to substrate defects and the like. The preparation method has simple process, obtains the suspended silicon disc structure which is supported by the column and has smooth edge, and can reduce the bending loss of the structure and the scattering loss caused by rough side surface.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.