Analysis of a-Si:H/TCO contact resistance for the Si heterojunction back-contact solar cell

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• 作者：Seung-Yoon Lee ; Hongsik Choi ; Hongmei Li ; Kwangsun Ji ; Seunghoon Nam ; Junghoon Choi ; Seh-Won Ahn ; Heon-Min Lee ; Byungwoo Park
• 关键词：Amorphous Si ; Heterojunction back-contact solar cell ; Contact resistance
• 刊名：Solar Energy Materials and Solar Cells
• 出版年：January, 2014
• 年：2014
• 卷：120
• 期：part_PA
• 页码：412-416
• 全文大小：1066 K

文摘

The contact resistance of amorphous Si (a-Si:H)/transparent-conducting oxide (TCO) is evaluated and analyzed in terms of the contribution to the series resistance (R_s) and fill factor (FF) in the Si heterojunction back-contact (HBC) solar cell. It is shown that p-a-Si:H (emitter) and n-a-Si:H (back surface field: BSF)/TCO contact resistance are of similar values (0.37-38 惟 cm²) which are much higher than those of doped crystalline Si/metal contacts used in conventional Si solar cells. Of some factors affecting R_s loss in the HBC solar cell, BSF/TCO contact is the most significant one when considering the contact area. By interleaving the n-type microcrystalline Si (n-渭c-Si) between n-a-Si:H and TCO, 6-inch HBC solar cell with 20.5% efficiency is obtained, which was attributed to the reduced R_s and improved FF. It is noteworthy that the variations of R_s and FF are well estimated by measuring BSF-contact resistance, and are close to the empirical data: reduction in R_s to 1.77 惟 cm² and the increase in FF by 6.0% compared to the cell without n-渭c-Si interface layer. The results indicate that there is much room for higher efficiency by reducing the emitter- and BSF-contact resistance. Nonetheless, the method developed here can be a powerful tool to analyze the resistance component in HBC cell.