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Corrosion method of CdTe film solar cell

A thin-film solar cell and thin-film technology, which is applied in circuits, photovoltaic power generation, electrical components, etc., can solve the problems of strong volatility of bromo-methanol corrosive solution, unfavorable industrial production, and toxicity.

Inactive Publication Date: 2009-10-28
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Usually, bromomethanol corrosion and phosphorous nitric acid corrosion are used for chemical etching of the surface of CdTe film. Studies have shown that when bromine methanol is used to corrode CdTe solar cells, bromine often penetrates the CdTe film and even reaches the CdTe / CdS interface. Strong, poisonous, not conducive to industrial production; industrial production often uses phosphorus nitric acid corrosion, but the disadvantage is that there is preferential corrosion, especially corrosion along the grain boundary, which causes metal ions or impurities to diffuse along the grain boundary, forming a conductive bypass road

Method used

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  • Corrosion method of CdTe film solar cell
  • Corrosion method of CdTe film solar cell
  • Corrosion method of CdTe film solar cell

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] (1) When the temperature of the corrosive solution is controlled at 40°C, the sample is put into the corrosive solution, and the corrosive solution is 65% to 68% nitric acid, 99.5% glacial acetic acid and deionized water in a ratio of 1: 100:40 volume ratio mixing, the added NaAc is 15g / L, and the corrosion time is 1 minute.

[0017] (2) Take out the sample, rinse it several times with deionized water, and dry it with nitrogen.

[0018] (3) Co-sputter high-purity ZnTe target (99.999%) and Cu target (99.999%) by sputtering method or vacuum co-evaporation method to evaporate high-purity ZnTe source (99.999%) and copper source (99.999%), the deposition thickness is about 100nm, annealed at ~190°C, and then deposited ~200nm metal electrode Ni.

Embodiment 2

[0020] (1) When the temperature of the corrosive solution is controlled at 35°C, the sample is put into the corrosive solution, and the corrosive solution is 65% to 68% nitric acid, 99.5% glacial acetic acid and deionized water in a ratio of 1: 100:30 volume ratio mixing, the added NaAc is 15g / L, and the corrosion time is 2 minutes.

[0021] (2) Take out the sample, rinse it several times with deionized water, and dry it with nitrogen.

[0022] (3) Coat the surface of the corroded CdTe with 10% HgTe:Cu / 90% graphite slurry, anneal in nitrogen for 20 minutes at a temperature of 290° C., and then deposit 100 nm of Au as a metal electrode.

Embodiment 3

[0024] (1) When the temperature of the corrosive solution is controlled at 30°C, the sample is put into the corrosive solution, and the corrosive solution is 65% to 68% nitric acid, 99.5% glacial acetic acid and deionized water with a ratio of 1.5: 100:30 volume ratio mixing, the added NaAc is 20g / L, and the corrosion time is 3 minutes.

[0025] (2) Take out the sample, rinse it several times with deionized water, and dry it with nitrogen.

[0026] (3) co-sputtering high-purity Sb target (99.999%) and Te target (99.999%) by sputtering method or vacuum co-evaporation method to evaporate high-purity Sb source (99.999%) and Te source (99.999%), the deposition rate ratio (0.4~0.7), the thickness is about 100nm, annealed to 200°C, and Ni / Al electrode (Ni: 50nm; Al: 3μm) is deposited.

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Abstract

The invention relates to a method for surface corrosion of a CdTe film and preparation of a CdTe solar cell by adopting the method, pertaining to the processing field of semiconductor devices. An mixed liquid of nitric acid, glacial acetic acid, NaAc and deionized water is served as corrosive liquid, wherein, the NaAc is served as a buffering agent to keep the pH value of the intermixture unchanged and lead the reaction to be more stable; CdTe and the nitric acid react to generate a layer rich in tellurium; after washing and blow-drying, a back contact layer containing Cu or without Cu is sedimented; finally, a back electrode is sedimented for preparing the CdTe solar cell. Sedimentation of back contact material can increase carrier concentration near a pn junction, reduce the height of Schottky potential barrier and avoid direct sedimentation of Cu from forming a comparatively complex CuxTe structure. By adopting the method for corrosion and the preparation of the CdTe solar cell, the performance of the solar cell can be obviously improved and the stability and the repeatability of the device can be ensured.

Description

technical field [0001] The invention belongs to the field of semiconductor device processing, in particular to the surface corrosion of CdTe thin films and the preparation of CdTe solar cells by the method. Background technique [0002] The basic structure of a CdTe solar cell is: glass substrate (G) / transparent conductive film (T) / n-CdS(W) / p-CdTe(A) / back electrode (M), such as figure 1 shown. The back electrode is often made of metal, but CdTe has a high work function (5.5eV), and it is difficult to find a metal with a high work function to form an ohmic contact with it, which greatly affects the performance of the solar cell. [0003] At present, the solution is to etch the surface of the CdTe film first, and then deposit the back contact layer material. Usually, bromomethanol corrosion and phosphorous nitric acid corrosion are used for chemical etching of the surface of CdTe film. Studies have shown that when bromine methanol is used to corrode CdTe solar cells, bromine...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L31/18H01L31/042H01L31/0224H01L21/465
CPCY02E10/52Y02E10/50Y02P70/50
Inventor 冯良桓李卫蔡亚平武莉莉
Owner SICHUAN UNIV
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