LATERAL COMPOSITION MODULATED GalnP FOR HIGH EFFICIENCY TANDEM SOLAR CELLS

摘要

For tandem solar cells, increasing the generated photocurrent due to absorption of sunlight and minimizing recombination of generated minority carriers is crucial for improving the solar cell performance which is possible by using lateral composition modulated (LCM) structure. LCM GalnP has a smaller band gap compared to bulk GalnP, and using them in the top cell of multi-junction solar cell is effective for increasing the light absorption and the generated photocurrent. In this work we investigate the effect of embedding LCM GalnP on the solar cell performance. Simulation results reveal that for LCM GalnP layer thickness up to 40 nm, the efficiency of the solar cell can be increased. This is due to the increase in open circuit voltage owing to the increased light absorption by both In-rich and Ga-rich GalnP layers of LCM structure. With further increase in LCM GalnP layer thickness, the increase in efficiency is due to the increase in short circuit current density which is attributed to the enhanced light absorption by the In-rich GalnP. These results show the potential of LCM GalnP structure as the top cell material for realizing high-efficiency multi-junction tandem solar cells.