Fast Photoluminescence Imaging of Silicon Wafers

Abstract

Photoluminescence (PL) imaging is demonstrated as a fast characterization tool allowing variations of the minority carrier lifetime within large area silicon wafers to be measured with high spatial resolution and with a data acquisition time of only one second. PL imaging is contactless and can therefore be applied to silicon solar cells before and after every processing stage including fully processed cells and bare, unpassivated mc-Si wafers, which makes it an extremely effective process monitoring tool that is ideally suited for inline applications in the PV industry. The combination of PL imaging with electroluminescence imaging and the application of PL imaging with external bias control are demonstrated to give very quick access to additional valuable information about local series resistance variations