Analysis of Band Alignment Engineering and Interface Defects on a GaAs/GaSb Heterostructure Solar Cell

Abstract

In photovoltaic sector, optimal utilization of the solar spectrum combined with improved power conversion efficiency is the call of the day. Such elasticity is provided by heterostructure solar cells. But it is found that with a high lattice mismatch and band discontinuities, the open‐circuit voltage (Voc) and the fill factor deteriorates handsomely. As a result, the second requirement is still unsatisfied. To address such issues, band alignment engineering is introduced in this paper. Silvaco ATLAS is used to virtually create and verify the proposed model. Herein, different recombination events and their effects on the cell's Voc are investigated in depth. Furthermore, interface trap defect is introduced to investigate its effect on the lower efficiency and Voc. However, it is found that, in GaAs/GaSb heterostructures, the reduced Voc and efficiency issues can be avoided, because the proposed model is able to achieve a lower trap density of 105 cm−2.