Effects of Substrate Orientation on Photovoltaic Performance of InGaAs Solar Cells

Abstract

To investigate substrate orientation effect on the solar cell efficiency, In0.16Ga0.84As solar cells were grown on GaAs substrates with different miscut angles by metalorganic chemical vapor deposition. It was found that a p-n In0.16Ga0.84As solar cell grown on a 2°-off GaAs substrate exhibits better conversion efficiency than that grown on a 15°-off GaAs substrate. The poor performance of the 15°-off In0.16Ga0.84As solar cell could be attributed to the formation of high-density misfit dislocations through strain relaxation, which reduces minority carrier lifetime. The conversion efficiency of a 15°-off In0.16Ga0.84As solar cell could be improved by using a p-i-n structure. With the employment of the p-i-n structure design, a 15°-off In0.16Ga0.84As solar cell was demonstrated to show the conversion efficiency close to or even better than that of a 2°-off In0.16Ga0.84As solar cell with the same structure.