Characterization of silicon solar cells and substrates with the PVScan 5000

A laser scanning system, originally developed by NREL for the rapid characterization of crystal defects in single‐ and poly‐crystalline semiconductors, has been commercialized by Labsphere, Inc. as the PVScan 5000. In the unprocessed material, the system produces digital color maps of the spatial distributions of dislocations and grain boundaries simultaneously. After device fabrication, the PVScan 5000 is used to produce photoresponsivity maps of the light beam induced current (LBIC) on a photovoltaic device such as a solar cell or a photodetector. It also measures the spatial distributions of optical reflectance, both specular and diffuse, which can be applied to the LBIC maps to determine the internal responsivity of the device. It may be possible in the future to determine the diffusion length for certain devices.