Microcomputer controlled optical scanner for solar cell diagnostics

Abstract

In the present scanner for on-line solar cell defect analysis, a microcomputer is used to scan a 5-25 micron He-Ne laser spot over the solar cell in both the X and Y axes, while acquiring short circuit current or open circuit voltage at each point in the scanned area. For detailed defective region analysis, a fine scan is made, and such cell parameters as the recombination velocity and diffusion length around the defect region are calculated. The scanner has been used to study spatial variations in the performance of single crystal and polycrystalline Si solar cells, as well as thin film CdS/Cu₂S solar cells.