InGaN/GaN Multiple Quantum Wells Solar Cell as an Efficient Power Source for Space Mission

Abstract

A changeable band gap and radiation hard ternary indium gallium nitride (InGaN) with multiple quantum well (MQW) structure-based solar cell is numerically modelled and analysed for a better power source in space mission using modern TCAD tool. Since InGaN has direct band gap varying from 0.7 to 3.4 eV covering nearly the complete solar spectrum, it can be one of the best candidates for making efficient tandem solar cells. It is well known that the combination of InGaN/GaN multiple quantum well (MQW) structures in GaN-based devices drastically decreases surface recombination thereby improving cell performance. Here, a numerical simulation study of MQW InGaN/GaN solar cell with an active region formed by a number of InGaN quantum wells (QWs) separated by GaN quantum barriers (QBs) is investigated. It is found that there is no significant variation in cell parameters under the influence of indium content up to 25%. But, with the increase in the numbers of QW periods, the photovoltaic parameters, especially conversion efficiency, increases significantly. Under space AM0 solar illumination, the cell efficiency increases up to 8.2% for 20 MQW with 20% indium content of InGaN/GaN structure. And also, it gives better external quantum efficiency (EQE) up to 60% at 380 nm wavelength range near UV region. This clearly demonstrates that InGaN with GaN top cell and silicon bottom cell can definitely give broader and higher quantum efficiency.