[17p-Z29-1~10] 16.3 Bulk, thin-film and other silicon-based solar cells

[17p-Z29-7] Effects of intrinsic a-Si:H bilayers in silicon heterojunction solar cells

〇Hitoshi Sai¹, Hung-Jung Hsu², Po-Wei Chen², Pei-Ling Chen², Takuya Matsui¹ (1.AIST, 2.NCTU)

Keywords:solar cell, silicon, heterojunction

The impact of intrinsic amorphous silicon bilayers in amorphous silicon/crystalline silicon (a-Si:H/c-Si) heterojunction solar cells is investigated. Intrinsic a-Si:H films with a wide range of film density and hydrogen content are prepared with plasma-enhanced chemical vapor deposition (PECVD) technique by modifying various process parameters. Any a-Si:H film prepared in this work does not realize good surface passivation at the a-Si:H/c-Si interface if it is applied to SHJ solar cells as single i-layers. However, surface passivation is significantly improved by applying intrinsic bilayers, which are composed of a porous interfacial layer (~2 nm) and an overlying dense layer (~8 nm). The microstructure factor R* of the interfacial a-Si:H layer is closely correlates to the surface passivation capability of the bilayers. A variety of PECVD process parameters (temperature, pressure, or precursor gas species) can be utilized to grow an interfacial layer for good surface passivation, if its R* is controlled within a proper range.