Carrier transport via V-shaped pits in InGaN/GaN MQW solar cells

摘要

Carrier transport via the V-shaped pits (V-pits) in InGaN/GaN multiple-quantum-well (MQW) solar cells is numerically investigated.By simulations,it is found that the V-pits can act as effective escape paths for the photo-generated carriers.Due to the thin barrier thickness and low indium composition of the MQW on V-pit sidewall,the carriers entered the sidewall QWs can easily escape and contribute to the photocurrent.This forms a parallel escape route for the carries generated in the flat quantum wells.As the barrier thickness of the flat MQW increases,more carriers would transport via the V-pits.Furthermore,it is found that the V-pits may reduce the recombination losses of carriers due to their screening effect to the dislocations.These discoveries are not only helpful for understanding the carrier transport mechanism in the InGaN/GaN MQW,but also important in design of the structure of solar cells.