Simulation of High-Efficiency GaN/InGaN p-i-n Solar Cell With Suppressed Polarization and Barrier Effects

The photovoltaic characteristics of Ga-face GaN/InGaN p-i-n solar cells are investigated numerically. The severe polarization and barrier effects induced by the GaN/InGaN hetero-interfaces are demonstrated to be detrimental for the carrier collection. The conversion efficiency could be degraded to be out of application when the degree of polarization and/or indium composition are high. To efficiently eliminate both critical issues, the solar cell structure with appropriate band engineering is introduced. In the proposed structure, the photovoltaic characteristics not only show high-grade performance but also become insensitive to the degree of polarization, even in the situation of high indium composition.