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Frontiers of Optoelectronics

Front Optoelec    2014, Vol. 7 Issue (1) : 46-52     DOI: 10.1007/s12200-013-0386-y
Texturization and rounded process of silicon wafers for heterojunction with intrinsic thin-layer solar cells
Kunpeng MA1,2, Xiangbin ZENG1,2(), Qingsong LEI1,3, Junming XUE3, Yanzeng WANG3, Chenguang ZHAO3
1. School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China; 2. Shenzhen Institute of Huazhong University of Science and Technology, Shenzhen 518000, China; 3. Hisunpv Technology Co., Ltd, Hebei 053000, China
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Heterojunction with intrinsic thin-layer (HIT) solar cells are sensitive to interface state density. Traditional texture process for silicon solar cells is not suitable for HIT one. Thus, sodium hydroxide (NaOH), isopropanol (IPA) and mixed additive were tentatively introduced for the texturization of HIT solar cells in this study. Then, a mixture including nitric acid (HNO3), hydrofluoric acid (HF) and glacial acetic acid (CH3COOH) was employed to round pyramid structure. The morphology of textured surface and the influence of etching time on surface reflectance were studied, and the relationship between etching time and surface reflectance, vertex angle of pyramid structure was analyzed. It was found that the mixture consisting of 1.1 wt% NaOH, 3 vol% IPA and 0.3 vol% additives with etching time of 22.5 min is the best for HIT solar cells under the condition of 80°C. Uniform pyramid structure was observed and the base width of pyramid was about 2–4 μm. The average surface reflectance was 11.68%. Finally the effect of different processes on the performance of HIT solar cells was investigated. It was shown that these texturization and rounding techniques used in this study can increase short circuit current (Jsc), but they have little influence on fill factor (FF) and open circuit voltage (Voc) of HIT solar cells.

Keywords texturization      reflectance      pyramid      heterojunction with intrinsic thin-layer (HIT) solar cells     
Corresponding Authors: ZENG Xiangbin,   
Issue Date: 05 March 2014
 Cite this article:   
Kunpeng MA,Xiangbin ZENG,Qingsong LEI, et al. Texturization and rounded process of silicon wafers for heterojunction with intrinsic thin-layer solar cells[J]. Front Optoelec, 2014, 7(1): 46-52.
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Kunpeng MA
Xiangbin ZENG
Qingsong LEI
Junming XUE
Yanzeng WANG
Chenguang ZHAO
Fig.1  Effects of etching time on the uniformity of reflectance across a wafer by five-point measurement
Fig.2  Reflectance spectra of polished, as-cut and textured wafers
Fig.3  SEM micrographs of silicon wafer with 22.5 min etching. (a) × 2000; (b) × 6000
Fig.4  Average reflectance of textured wafers at different etching times
Fig.5  SEM profiles of textured wafers for different etching times. (a) 0 s; (b) 2 s; (c) 40 s; (d) 60 s
Fig.6  Mass-transfer influenced etching
Fig.7  - curves of solar cells on polished wafer, and textured wafers with or without rounded process
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