Table of Contents
ISRN Renewable Energy
Volume 2011, Article ID 712872, 8 pages
http://dx.doi.org/10.5402/2011/712872
Research Article

Modeling and Optimization of Advanced Single- and Multijunction Solar Cells Based on Thin-Film a-Si:H/SiGe Heterostructure

Department of Electrical Engineering, Shahid Chamran University of Ahvaz, Ahvaz 61357-831351, Iran

Received 4 August 2011; Accepted 13 September 2011

Academic Editors: O. O. Fasina and B. S. Hyun

Copyright © 2011 Abdolnabi Kosarian and Peyman Jelodarian. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In amorphous thin-film p-i-n solar cell, a thick absorber layer can absorb more light to generate carriers. On the other hand, a thin i-layer cannot absorb enough light. Thickness of the i-layer is a key parameter that can limit the performance of solar cell. Introducing Ge atoms to the Si lattice in Si-based solar cells is an effective approach in improving their characteristics. Especially, current density of the cell can be enhanced without deteriorating its open circuit voltage, due to the modulation of material band-gap and the formation of a heterostructure. This work presents a novel numerical evaluation and optimization of an amorphous silicon double-junction structure thin-film solar cell (a-SiGe:H/a-Si:H) and focuses on optimization of a-SiGe:H mid-gap single-junction solar cell based on the optimization of the Ge content in the film, thickness of i-layer, p-layer and doping concentration of p-layer in a (p-layer a-Si:H/i-layer a-SiGe:H/n-layer a-Si:H) single-junction thin-film solar cell. Optimization shows that for an appropriate Ge concentration, the efficiency of a-Si:H/a-SiGe solar cell is improved by about 6.5% compared with the traditional a-Si:H solar cells.