Development of cathodoluminescence spectrum imaging characterization of CdTe solar cells

Abstract

To make renewable electricity cost-competitive with fossil fuel electricity, we must continue to improve photovoltaic (PV) and other renewable technologies. CdTe solar cells are a commercialized PV technology that is a leader in terms of both efficiency and cost. As CdTe solar cells approach theoretical or practical efficiency limits, we need robust characterization tools and data analysis to help guide empirical device development. Cathodoluminescence (CL) is a scanning electron microscope-based characterization technique that can probe the opto-electronic properties of solar cells with high spatial resolution. CL measurements can provide insight on recombination at the defect-scale and hence CL is useful for assessing the microscopic “roots” of macroscale device performance. This thesis concerns the development of a relatively new CL capability—known as CL spectrum imaging—for the characterization of recombination and defects in CdTe solar cells. The interpretation of CL spectrum imaging data and the potential for this technique as a root-cause diagnostic tool for CdTe solar cells is explored.