Performance Analysis of 0.4–1.2-μm CdTe Solar Cells

Thin-film cadmium telluride (CdTe) solar cells with an absorber thickness range of 0.4-1.2 μm were fabricated by close-space sublimation on a transparent MgZnO window layer. Microscopy cross sections showed that a significant fraction of the CdTe crystallites extended throughout the absorber layer, and capacitance measurements demonstrated that the absorbers were depleted into forward bias. Current and fill factor loss analyses were used to identify dominant loss mechanisms in the devices as a function of absorber thickness, and photoluminescence measurements were increasingly influenced by back-surface recombination as the absorber was made thinner. The thinner CdTe devices showed modest current and fill-factor reduction but overall good diode quality, and the highest efficiency of 15% was achieved with 1.2-μm CdTe.