Development of Two-photon excitation time-resolved photoluminescence microscopy for lifetime and defect imaging in thin film photovoltaic materials and devices

Two-photon excitation time resolved photoluminescence (2PE TRPL) is a powerful photovoltaic material analysis technique. It provides a rapid, contactless, and nondestructive method of determining semiconductor parameters such as surface and bulk carrier lifetime, which are indicative of overall device performance. We present a novel 2PE TRPL microscopy system of high spatial and temporal resolution, capable of detailed 3D analysis for PL emission intensity and minority carrier lifetime. Initial data shows PL intensity, lifetime, and diffusion length imaging in polycrystalline CdTe and indicates variations of diffusion coefficient and bulk lifetime in a polycrystalline CdTe sample.