Numerical Study on the Influence of Piezoelectric Polarization on the Performance of p-on-n (0001)-Face GaN/InGaN p-i-n Solar Cells

The influence of piezoelectric polarization on the performance of p-on-n (0001)-face GaN/InGaN p-i-n solar cells is investigated. Simulation results show that the energy band is tilted into the direction detrimental for carrier collection due to the polarization-induced electric field. When the indium composition of InGaN layer increases, this unfavorable effect becomes more serious which, in turn, deteriorates the device performance. This discovery demonstrates that, besides the issue of crystal quality, the problem caused by the polarization effect needs to be overcome for the development of GaN-based solar cells.