Abstract
Syringe-like ZnO nanorod arrays (NRAs) synthesized by a hydrothermal method were applied as the lightharvesting layer on InGaN-based multiple quantum well (MQW) solar cells. Theoretical calculations show that the NRAs with an abrupt shrinkage of tip diameter can further suppress surface reflectance in comparison with the flat NRAs. InGaN-based MQW solar cells with the syringe-like NRAs exhibit greatly improved conversion efficiencies by 36%. These results are attributed to the improved flatness of the refractive index profile at the air/ device interface, which results in enhanced light trapping effect on the device surface. (C) 2011 Optical Society of America