Numerical Study of Amorphous Silicon Based Solar Cell Performance Toward 15% Conversion Efficiency

A detailed theoretical analysis of a-Si based solar cells has been performed using a comprehensive computer simulation model in order to clarify the factors limiting the cell performance. We simulated how the solar cell characteristics are influenced by the variations of various factors. As a result, it was found that the solar cell performance was seriously affected by low conductivity in the a-SiC p-layer and the density of D-states in the i-layer. Based on all of the theoretical results, we predict that a conversion efficiency of over 15% can be potentially realized for the a-Si based single-junction solar cell when the enhancement of the carrier concentration in the p-layer (greater than 1018 cm-3) and the decrease of the density of D-states in the i-layer (to about one fifth of the present state-of-the-art value) are achieved and the device structure is optimized.