Photovoltaic Response of InGaN/GaN Multi-quantum Well Solar Cells Enhanced by Reducing p-type GaN Resistivity

Two InGaN/GaN multiple quantum well solar cells with different p-GaN layers are grown, and the effect of p-type GaN resistivity on the spectral response of the solar cells is investigated. It is found that the external quantum efficiency (EQE) increases obviously in the low-energy spectral range (λ > 360 nm), when the resistivity of p-GaN layer decreases. According to the calculation based on the C-V measurement, we believe the width of the depletion region increasing in MQW layer and decreasing in p-GaN layer with the reduction of p-type GaN resistivity is responsible for the variation of EQE. The resistivity of p-GaN layer, thus, should be reduced further for fabricating high conversion efficiency InGaN-based solar cells.