The Effects of a Low-Temperature GaN Interlayer on the Performance of InGaN/GaN Solar Cells

An InGaN/GaN p-i-n solar cell inserted with a 5-nm low-temperature (LT) GaN interlayer between the p-GaN cap layer and the InGaN i-layer is grown on a c-plane sapphire substrate by metal organic chemical vapor deposition. The effects of the LT GaN interlayer on the performance of the InGaN/GaN solar cells are investigated. It is found that the LT-GaN interlayer prevents the extension of threading dislocations from the InGaN layer to the p-GaN layer and improves the crystal quality of both the p-GaN cap layer and the InGaN i-layer, ultimately leading to an increasing external quantum efficiency and photocurrent density of the InGaN/GaN solar cells.