Photovoltaic Material Characterization With Steady State and Transient Photoluminescence

In this study, we develop an approach to characterize the surface and bulk properties for thin films of photovoltaic materials by combining two experimental photoluminescence (PL) techniques with one multiphysics simulation. This contactless, in-line characterization technique allows reliable extraction of key lifetime parameters. In this study, we first discuss the strengths and weaknesses of both steady-state and transient PL techniques (specifically, steady-state PL excitation spectroscopy and time-resolved PL) and show that combining them with numerical simulation can be used to extract surface and bulk lifetimes self consistently. The method is applied to InP thin films grown with a novel vapor-liquid-solid method. The InP thin film tested is found to have a bulk Shockley-Read-Hall (SRH) lifetime of 12 ns and a front surface recombination velocity of 5×10⁴ cm/s.