The impact of piezoelectric polarization and nonradiative recombination on the performance of (0001) face GaN/InGaN photovoltaic devices

摘要

The impact of piezoelectric polarization and nonradiative recombination on the short-circuit current densities (J_(sc)) of (0001) face GaN/InGaN photovoltaic devices is demonstrated. P-i-n diodes consisting of 170 nm thick intrinsic In_(0.09)Ga_(0.91)N layers sandwiched by GaN layers exhibit low J_(sc)～40 μA/cm~2. The piezoelectric polarization at the GaN/lnGaN heterointerfaces creates drift currents opposite in direction needed for efficient carrier collection. Also, nonradiative recombination centers produce short carrier lifetimes, limiting J_(sc). Alternative structures with intrinsic InGaN layers sandwiched by ?-type InGaN or graded In_yGa_(1-y)N (y=0-0.09) layer and a p-type In_(0.015)Ga_(0.985)N layer have favorable potentials, longer carrier lifetimes, and improve J_(sc) to ～0.40 mA/cm~2.