Hydrogen-rich c-Si interfacial modification to obtain efficient passivation for silicon heterojunction solar cell

• Published in: Journal of materials science. Materials in electronics Vol. 31; no. 17; pp. 14608 - 14613
• Main Authors: You, Jiachuan, Liu, Huan, Qu, Minghao, Yu, Cao, Zhao, Lei, Xu, Xixiang, Wang, Wenjing
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.09.2020; Springer Nature B.V
• Subjects: Amorphous silicon; Carrier lifetime; Characterization and Evaluation of Materials; Chemistry and Materials Science; Contact pressure; Heterojunctions; Hydrogen storage; Materials Science; Minority carriers; Open circuit voltage; Optical and Electronic Materials; Passivity; Photovoltaic cells; Plasma enhanced chemical vapor deposition; Silicon; Solar cells
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-020-04023-0

How to passivate the heterojunction between the doped layer and the crystalline silicon (c-Si) base plays a crucial role for the silicon heterojunction (SHJ) solar cell to obtain high performance, especially high open-circuit voltage ( V OC ) and fill factor (FF). Here, a hydrogen-rich c-Si interfacial modification was realized by preparing an ultrathin (~ 1.5 nm) intrinsic hydrogenated amorphous silicon (a-Si:H) onto the c-Si(n) interface with pure silane via plasma enhanced chemical vapor deposition (PECVD), prior to the deposition of a ~ 8 nm relatively compact a-Si:H(i) layer for the a-Si:H(p)/c-Si(n) heterojunction. The enhanced effective minority carrier lifetime ( τ eff ) of the c-Si base and V OC of the final solar cell indicated that such interfacial modification improved the heterojunction passivation efficiently by saturating the c-Si dangling bonds (DBs) via hydrogenation with the following deposition of the compact a-Si:H(i) layer that kept the c-Si interface out of direct contact with the doped layer. By altering the deposition pressure, the hydrogen content ( C H ) in the ultrathin a-Si:H was adjusted regularly to fabricate a series of SHJ solar cells with the area of 244.45 cm 2 . A maximal conversion efficiency up to 23.81% was achieved with V OC of 742.9 mV, J SC of 38.67 mA/cm 2 and FF of 82.99% when the ultrathin a-Si:H had a relatively high C H of about 24–25%.