Analysis of poly-Si thin film p⁺-n-n⁺ homojunction solar cell and heterojunction solar cell with and without a thin μc-Si layer at the interface of a-Si and poly-Si layers

Institute of Electronics Engineering, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan, Republic of China

Corresponding author: ajletha@hotmail.com

Received: 2 December 2008
Revised: 15 January 2009
Accepted: 28 January 2009
Published online: 27 March 2009

Abstract

In this study, new possibilities for higher efficiency poly-Si thin film solar cells are investigated using MEDICI^TM device simulator. The poly-Si p⁺-n-n⁺ thin film solar cell with a thin a-Si p⁺ layer is found to have higher efficiency than the homojunction p⁺-n-n⁺ cell. Further improvement in efficiency of the heterojunction p⁺-n-n⁺ cell is achieved by introducing a thin μc-Si layer at the interface of a-Si emitter and poly-Si absorber layers. The μc-Si layer at the interface is found to reduce the recombination losses at the interface and improved the fill factor and efficiency of the cell. The photovoltaic parameters of the cell and the absorber layer thickness for optimum efficiency are highly influenced by grain size and passivation at the grain boundary.