Amorphous Cu-Sb-S based semiconductors for thin-film solar cell applications

We report on the disposition and characterization of Cu-Sb-S based amorphous semiconductor films grown by magnetron sputtering of a Cu-Sb-S home-made target. We find that the Cu-Sb-S films deposited at 150°C exhibit the amorphous phase and have high optical absorptions with a band gap at ~2.0eV and weaker absorptions due to the fringe effect of the thin-film. X-ray diffraction displays no clear crystal morphology consistent with scanning electron microscopy imaging showing a grain-less, smooth, and densely packed microstructure. Our Cu-Sb-S based thin-film solar cells exhibit clear diode characteristics. The best cell measured under an AM1.5 illumination presents an open-circuit voltage of 365mV and a FF of 51.6%. However, due to the low short-circuit current of only about 1 mA/cm2, the conversion efficiency is only 0.17%.