We report hybrid n-ZnO/i-InGaN/p-GaN solar cells in which the n-GaN layer of n-GaN/i-InGaN/p-GaN solar cell was replaced with n-type ZnO. In this study, inverted structures were used for hybrid ZnO/nitride solar cells where p-type GaN was first grown on sapphire substrate, followed by i-InGaN and n-ZnO layers. The as-fabricated device showed high series resistance and low energy conversion efficiency due to the formation of damaged p-GaN region during dry etching. On the other hand, formation of microrods on the p-GaN eased the removal of the damaged p-GaN resulting in significantly lowered series resistance and enhanced energy conversion efficiency.
(a) n-ZnO/i-InGaN/p-GaN solar cell structure without microrods, (b) n-ZnO/i-InGaN/p-GaN solar cell structure with microrods, and (c) magnified image of the dashed box on (b).