Design guidelines of InGaN nanowire arrays for photovoltaic applications

Abstract

III-Nitride NanoWire array Solar Cells (NWSCs) combine the inherent properties of III-N semiconductors with waveguiding and confinement properties of nanowire arrays. In the present paper, some design guidelines of NWSCs made from Indium-Gallium-Nitride InGaN alloys are presented. Firstly, a detailed balance analysis was performed to show the importance of using InGaN materials to effectively convert the light to electricity, followed by an optical modelling to point out the advantages of using periodic nanowire arrays in designing solar cells. From the detailed balance analysis, it is expected that single junction solar cells made from In0.63Ga0.37N alloy result in the highest light-to-electricity conversion efficiency of 31%, and the Rigorous Coupled Wave Analysis RCWA simulations show that nanowire arrays made from InxGa1-xN fractions (x values) ranging between 50 and 77% alloys may achieve efficiencies of more than 33%, with a maximum efficiency of 37.7% for In0.67Ga0.33N NW array. Substrate choice, array density and filling material impacts on device performance were also studied.