Photoluminescence Imaging of Silicon Wafers and Solar Cells With Spatially Inhomogeneous Illumination

Photoluminescence imaging is a fast and powerful spatially resolved characterization technique, commonly used for silicon wafers and solar cells. In conventional measurements, homogeneous illumination is used across the sample. In this paper, we present a photoluminescence imaging setup that enables inhomogeneous illumination with arbitrary illumination patterns to determine various parameters of solar cells and solar cell precursors. To demonstrate the strength of the proposed inhomogeneous illumination imaging, a set of proof-of-concept measurements have been conducted; these measurements include contactless series resistance imaging, emitter sheet resistance, and diffusion length measurements. The results indicate that the use of inhomogeneous illumination significantly extends the range of photoluminescence imaging applications for the characterization of silicon wafers and solar cells.