Impurity-related photovoltaic efficiency of (In,Ga)N/GaN quantum well-single intermediate band solar cell considering heavy hole impact

摘要

Impurity-related photovoltaic conversion efficiency of single-intermediate band solar cell based on (In, Ga)N/GaN QW embedded in the intrinsic region of conventional p-i-n structure is reported in the present paper. The width and position of ground-state intermediate band originated from electron and hole discrete quantized energy levels are calculated by solving impurity-related Schrodinger equation based on the finite difference method. Inter-subband and inter-band transitions are obtained for different structure sizes and indium concentrations. Considering the impurity and hole generally ignored in such study, open-circuit voltage, current density and photovoltaic efficiency are numerically calculated. Our results show that the structure mean size and composition can be adjusted to optimize the performance of solar cell. It is found that: (1) the efficiency decreases with respect to well size and chemical composition (2) Two different behaviors limited by a critical barrier size are obtained, and (3) the critical barrier size increases versus the well composition.