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 V_(OC). This is because the enhanced optical absorption by light trapping effect facilitated more vigorous photon recycling in the active region of the cell.