Polarization-Engineered InGaN/GaN Solar Cells: Realistic Expectations for Single Heterojunctions

The photovoltaic properties of (0 0 0 1) n-InGaN/p-GaN single heterojunctions were investigated numerically and compared with those of conventional p-GaN/i-InGaN/n-GaN structures, employing realistic material parameters. This alternative device architecture exploits the large polarization fields, and high-efficiency modules are achieved for In-rich, partially relaxed, and coherently strained InGaN films. In addition, with the appropriate band and piezoelectric engineering, a feasible device is proposed, reaching a conversion efficiency up to 14.5% under AM1.5G illumination, revealing the true potential of InGaN single-junction solar cells with proper design.