LAUSR

In this article, we introduce time-resolved fluorescence imaging as an optical characterization method for optoelectronic devices. Under wide-field illumination, it allows obtaining time-resolved photoluminescence maps with a temporal resolution of 500 ps and a micrometric spatial resolution. An experiment on a GaAs-based solar cell is presented here as a proof of concept. Thanks to a model including diffusion and recombination of minority charge carriers, we fit the experimental photoluminescence transients and extract key optoelectronic properties for the considered device. For various fluence levels, we determine an intrinsic bulk recombination lifetime τn = 75 ns, a constant effective diffusion length Leff = 190 μm, which is characteristic for the lateral transport inside the solar cell, and an injection-dependent contact recombination velocity Sn, taking its values between 7 × 104 and 3 × 105 cm/s, which is explained by the saturation of defects. The wide-field illumination notably avoids lateral dif...