Optical analysis of the photon recycling effect in InGaAs/GaAsP multiple quantum well solar cell with light trapping structure

摘要

Optical evaluation of the GaAs single junction solar cell with InGaAs/GaAsP strain balanced multiple quantum wells (SB-MQWs) was attempted. In order to estimate the photon recycling (PR) effect for different effective optical path lengths in optically-thin MQWs, a quantitative analysis of electroluminescence (EL) was applied for the MQWs solar cells with and without light trapping texture on the rear surface. By external quantum efficiency measurement, a clear improvement in MQWs absorption was obtained by rear surface texturing of the semi-insulating GaAs substrate with epitaxially grown PV active layer. Upon EL measurement under carrier injection, the cell with light trapping texture showed increased EL photon emission, indicating the enhancement of VOC. This is because the enhanced optical absorption by light trapping effect facilitated more vigorous photon recycling in the active region of the cell.