Double-sided germanium-based thermal radiation photovoltaic device structure and preparation method

Abstract

The invention relates to a double-sided germanium-based thermal radiation photovoltaic device structure and a preparation method thereof. The method comprises the following steps: S1, carrying out double-sided polishing treatment on a P-type germanium wafer; s2, depositing a phosphorus-doped nanocrystalline silicon thin film layer on one surface of the P-type germanium wafer to obtain a front surface; s3, annealing the P-type germanium wafer to obtain a phosphorus-doped silicon germanium layer; s4, sequentially carrying out a-SiCx, Al2O3 and a-SiC laminated film deposition on the back surface of the P-type germanium wafer; 5, processing an aluminum film pattern layer on the back surface of the P-type germanium wafer by adopting a template adding mode; s6, carrying out ITO deposition on the front surface of the P-type germanium wafer; s7, irradiating an aluminum film area on the back surface by adopting infrared laser, and doping an aluminum element part into the germanium substrate to form contact; and S8, printing a low-temperature silver paste electrode on the front surface of the P-type germanium sheet by adopting a silk-screen printing process to form an electrode. According to the structure and the preparation method of the thermophotovoltaic device capable of converting infrared radiation light into electricity, double-sided light receiving is achieved, and the thermophotovoltaic device is suitable for application scenes with radiation sources on both sides.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of thermal radiation photovoltaic power generation, and particularly relates to a double-sided germanium-based thermal radiation photovoltaic device structure and a preparation method. BACKGROUND

[0002] The thermal photovoltaic technology is a technology for directly converting the photon energy emitted by a high-temperature thermal radiator into electric energy through a semiconductor p-n junction. Since the TPV system can use various heat sources to provide fuel for the TPV system, the TPV technology has many potential applications, such as combined heat and power in residential applications, power generation in spacecraft, power for thermal energy storage systems or waste heat recovery in heavy industrial processes, waste heat recovery of photovoltaic systems to reduce the temperature of photovoltaic modules, improve the power generation efficiency of photovoltaic modules and reduce the risk of high temperature.

[0003] At present, the commonly known thermal photovoltaic cells in the field of research are Si, GaSb, InGaAs and the like. Si is used for thermal photovoltaic cells, and the band gap (1.1 eV) thereof is relatively high, and it is difficult to absorb and utilize infrared long-wave photons with a wavelength greater than 1100 nm. The band gap of GaSb, InGaAs and the like is relatively low, which is more reasonable, but the preparation cost is high. A feasible alternative solution of this method includes using crystalline germanium (E gap = 0.67 eV) as a photon absorber. Although germanium is an indirect band gap semiconductor, compared with other low band gap materials such as InGaAs, the absorption coefficient thereof is low, but the advantage of germanium for the TPV system mainly comes from the cost angle. On the one hand, germanium silicon wafer is cheaper than InP. On the other hand, the expensive epitaxial technology can be avoided, because germanium, as a group IV material, is highly compatible with silicon technology, allowing the implementation of thin film deposition technologies such as PECVD and ALD, which are standard methods in the silicon solar cell industry. Therefore, although there are inherent limitations, the germanium-based technology is a microcosm of a cost-effective strategy for developing TPV cells, and has a feasible prospect of industrial scalability.

[0004] The application proposes a new TPV device preparation method based on amorphous silicon carbide (a-SiCx) and aluminum oxide (Al2O3) thin film passivation, which can receive thermal radiation on both sides. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a double-sided germanium-based thermal radiation photovoltaic device structure and a preparation method, which can convert infrared radiation into electric thermal photovoltaic device structure and preparation method, and has double-sided light receiving, which is suitable for application scenarios with radiation sources on both sides.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows: The double-sided germanium-based thermal radiation photovoltaic device preparation method of the present application comprises the following processes: S1 carries out double-side polishing treatment on the P-type germanium sheet; S2 adopts PECVD or PVD mode to deposit phosphorus-doped nanocrystalline silicon film layer on one side of the P-type germanium sheet, to obtain a front side; S3 carries out annealing on the P-type germanium sheet, to make phosphorus further diffuse into the germanium body, to obtain a phosphorus-doped silicon germanium layer; S4 sequentially deposits a-SiCx, Al2O3, a-SiC stacked film on the back side of the P-type germanium sheet; S5 processes an aluminum film pattern layer on the back side of the P-type germanium sheet by adopting a template mode; S6 carries out ITO deposition on the front side of the P-type germanium sheet; S7 adopts infrared laser irradiation on the aluminum film area on the back side, to partially dope aluminum element into the germanium substrate to form a contact; S8 adopts a screen printing process to print a low-temperature silver paste electrode on the front side of the P-type germanium sheet, to form an electrode.

[0007] Further, S5 adopts a thermal evaporation or magnetron sputtering mode to process the aluminum film pattern layer.

[0008] Further, the wavelength of the infrared laser in S7 is 1064 nm, and the laser width is 30-150 microns.

[0009] Further, the annealing process parameters in S3 are that the temperature is between 600-800 ℃, and the annealing time is 30-100 min.

[0010] Further, the low-temperature silver paste electrode in S8 is processed by adopting a low-temperature sintering process with a temperature of 150-250 ℃ and a processing time of 15-40 min.

[0011] The application also claims to protect a double-side germanium-based thermal radiation photovoltaic device, which is made by the preparation method in any one of claims 1 to 5.

[0012] Further, the thickness of the nanocrystalline silicon film layer is 15-30 nm.

[0013] Further, the aluminum film pattern is a line pattern with a width of 100-200 microns and a pitch of 300-1000 microns.

[0014] Further, the thickness of the ITO layer is 70-90 nm.

[0015] The beneficial effects of the application are: The double-side light receiving is suitable for a double-side radiation application scenario, and the comprehensive infrared radiation photoelectric conversion efficiency is high, and the power generation capacity is large. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1Structure diagram of the double-sided germanium-based thermal radiation photovoltaic device of the present application; Figure 2 Process flow diagram of the preparation method of the present application; In the figure, 1-ITO layer, 2-nc-Si(n+) layer, 3-SiGe(n) layer, 4-a-SiCx layer, 5-Al2O3 layer, 6-a-SiC layer. DETAILED DESCRIPTION

[0017] For the convenience of those skilled in the art, the present application will be further described below in conjunction with the embodiments and the accompanying drawings. The content mentioned in the embodiments is not a limitation of the present application.

[0018] The double-sided germanium-based thermal radiation photovoltaic device preparation method provided by the present application comprises the following processes: S1. Double-sided polishing treatment is performed on a P-type germanium wafer; S2. A phosphorus-doped nanocrystalline silicon thin film layer is deposited on one side of the P-type germanium wafer by PECVD or PVD to obtain a front side; S3. Annealing is performed on the P-type germanium wafer to allow phosphorus to further diffuse into the germanium body to obtain a phosphorus-doped silicon germanium layer; S4. a-SiCx, Al2O3, and a-SiC stacked film deposition film are sequentially performed on the back side of the P-type germanium wafer; S5. An aluminum film pattern layer is processed on the back side of the P-type germanium wafer by using a template; S6. ITO deposition is performed on the front side of the P-type germanium wafer; S7. Infrared laser irradiation is performed on the aluminum film area on the back side to partially dope aluminum elements into the germanium substrate to form a contact; S8. A low-temperature silver paste electrode is printed on the front side of the P-type germanium wafer by using a screen printing process to form an electrode.

[0019] The photovoltaic device prepared by using the preparation method provided by the present application can receive light on both sides and is suitable for a double-sided radiation application scenario. The comprehensive infrared radiation photoelectric conversion efficiency is high, and the power generation capacity is large.

[0020] Embodiment 1:

[0021] Reference Figure 2 As shown in the figure, the double-sided germanium-based thermal radiation photovoltaic device preparation method comprises the following steps: 1. A P-type germanium wafer with a resistivity of 0.1-5 Ω·cm is subjected to double-sided polishing treatment; 2. A phosphorus-doped nanocrystalline silicon thin film layer is deposited on one side (front side) by PECVD or PVD, with a thickness of 15-30 nm and a doping concentration of 1E16-1E20 cm-3; 3. Annealing between 0-800℃ for 30-100min, phosphorus diffuses further into the germanium body, forming a phosphorus-doped silicon germanium layer with a thickness of 5-15nm; 4. The back surface is deposited with a-SiCx / Al2O3 / a-SiC stacked film by one of PECVD, ALD, PVD and the like; 5. The back surface is coated with a patterned aluminum film with a thickness of 1-10 microns by thermal evaporation, magnetron sputtering and the like, and a mask is used to form a width of 100-200 microns and a spacing of 300-1000 microns; 6. The front surface is deposited with ITO by PVD, with a thickness of 70-90nm; 7. The aluminum element in the aluminum film on the back surface is partially laser-doped into the germanium substrate by infrared laser (wavelength 1064nm) to form a contact, with a laser width of 30-150 microns; 8. The front surface is printed with a low-temperature silver paste electrode by a screen printing process, and the electrode is formed by low-temperature sintering at 150-250℃ for 15-40min.

[0022] Example 2:

[0023] This embodiment is a double-sided germanium-based thermal radiation photovoltaic device structure prepared by the above preparation method, which comprises, from top to bottom, an ITO layer 1, an nc-Si(n+) layer 2, a SiGe(n) layer 3, an a-SiCx layer 4, an Al2O3 layer 5, and an a-SiC layer 6.

[0024] The present application has many specific application approaches, and the above description is only a preferred embodiment of the present application. It should be noted that for ordinary skilled persons in the technical field, several improvements can be made without departing from the principles of the present application, and these improvements should also be considered as the protection scope of the present application.

Claims

1. A method for fabricating a double-sided germanium-based thermal radiation photovoltaic device, characterized in that, The method includes the following procedures: S1 performs double-sided polishing on P-type germanium wafers; S2 deposits a phosphorus-doped nanocrystalline silicon thin film layer on one side of the P-type germanium wafer using PECVD or PVD to obtain the front side; S3 annealed the P-type germanium sheet to allow phosphorus to diffuse further into the germanium matrix, resulting in a phosphorus-doped silicon-germanium layer. S4 deposits a-SiCx, Al2O3, and a-SiC stacked films sequentially on the back side of the P-type germanium wafer; S5 uses a template method to process an aluminum film pattern layer on the back of the P-type germanium sheet; S6 performs ITO deposition on the front side of the P-type germanium wafer; S7 uses infrared laser to irradiate the aluminum film area on the back side, and partially dopes aluminum elements into the germanium substrate to form a contact. S8 uses a screen printing process to print a low-temperature silver paste electrode on the front side of the P-type germanium sheet to form an electrode.

2. The method for fabricating a double-sided germanium-based thermal radiation photovoltaic device according to claim 1, characterized in that, The S5 is processed by thermal evaporation or magnetron sputtering to obtain an aluminum film pattern layer.

3. The method for fabricating a double-sided germanium-based thermal radiation photovoltaic device according to claim 1, characterized in that, The wavelength of the infrared laser in S7 is 1064nm, and the laser width is 30-150 micrometers.

4. The method for fabricating a double-sided germanium-based thermal radiation photovoltaic device according to claim 1, characterized in that, The parameters for the annealing process in S3 are: temperature between 600-800℃ and annealing time between 30-100min.

5. The method for fabricating a double-sided germanium-based thermal radiation photovoltaic device according to claim 1, characterized in that, The low-temperature silver paste electrode in S8 is processed using a low-temperature sintering process with a temperature of 150-250℃ and a processing time of 15-40 minutes.

6. A double-sided germanium-based thermal radiation photovoltaic device, characterized in that, The device is fabricated using any one of the preparation methods described in claims 1 to 5.

7. The double-sided germanium-based thermal radiation photovoltaic device according to claim 6, characterized in that, The thickness of the nanocrystalline silicon thin film layer is 15-30 nm.

8. The double-sided germanium-based thermal radiation photovoltaic device according to claim 6, characterized in that, The aluminum film pattern is a line pattern with a width of 100-200 micrometers and a spacing of 300-1000 micrometers.

9. The double-sided germanium-based thermal radiation photovoltaic device according to claim 6, characterized in that, The thickness of the ITO layer is 70-90nm.

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