Evaluation of Spin-Coated Alumina Passivation Layer for Point-Contacted Rear Electrode Passivation of Silicon Solar Cells

Ryosuke WATANABE  Tsubasa KOYAMA  Yoji SAITO  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E100-C   No.1   pp.101-107
Publication Date: 2017/01/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E100.C.101
Type of Manuscript: PAPER
Category: Semiconductor Materials and Devices
Keyword: 
silicon solar cells,  surface passivation,  alumina,  sol-gel,  

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Summary: 
We fabricated silicon solar cells with spin-coated sol-gel alumina passivation layers on the rear side. Spin-coated alumina passivation films have moderate passivation quality and are inferior to atomic layer deposited passivation films. However, low-cost and low temperature process of the sol-gel deposition is still beneficial for the cells using commercially available Cz silicon wafers. Thus, we consider an applicability of the spin-coated alumina passivation layer for rear side passivation. Dependence of cell efficiency on contact spacing and contact diameter of a rear electrode was investigated by both experiments and numerical calculation. The experimental results indicated that conversion efficiency of the cell is enhanced from 9.1% to 11.1% by optimizing an aperture ratio and contact spacing of the rear passivation layers. Numerical calculation indicated that small contact diameter with low aperture ratio of a rear passivation layer is preferable to achieve good cell performance in our experimental condition. We confirmed the effectivity of the spin-coated alumina passivation films for rear surface passivation of the low-cost silicon solar cells.