Fabrication and optimization of novel structure silicon heterojunction solar cells.

摘要

Silicon Heterojunction (SHJ) solar cell is a structure with a-Si emitters, passivation and base contacts deposited by low temperature plasma enhanced chemical vapor deposition (PECVD) on Si bulk materials. It paves a way to high efficiency solar energy conversion with affordable costs. However, optical loss due to front surface a-Si layer absorption and electrical loss due to inhibited carrier transport across a-Si passivation layer are two fundamental limitations in getting even higher efficiency.;In this work, device structures of SHJ solar cells are studied and optimized to reduce the two above limitations. Inverted pyramids via wet chemical etching are introduced on front surfaces of SHJ solar cells to suppress reflection loss. Further, both a-Si emitters and base contacts are relocated to the rear surface of device to form an interdigitated all back contact (IBC) structure. Carrier transport losses are investigated on the IBC structure.;In this work, it is found that (1) surface texturing brings an absolute 1.6% efficiency increase on front junction SHJ solar cells; (2) rear passivation is very critical to performance of IBC SHJ solar cells; (3) pilot run of SiNx as anti reflection coating (ARC) and rear side passivation has been done on IBC SHJ solar cells.