Electrical properties of zinc nitride and zinc tin nitride semiconductor thin films toward photovoltaic applications

Abstract

Zn3N2 (ZN) and ZnSnN2 (ZTN) are a promising class of nitride semiconductors for photovoltaic and light-emitting-diode applications due to their particular electrical and optical properties, elemental abundance and non-toxicity. So far, most of the experimental results show the degenerate carrier concentration. However, we find that low-temperature growth of these films in a chamber with ultra-high background vacuum can attain a non-degenerate electrical conductivity. This work provides the recent progress of the electrical properties of ZN and ZTN semiconductor thin films. The origins for the high carrier concentrations in ZN and ZTN have been discussed, demonstrating that non-intentional oxygen and hydrogen-related defects play significant roles in such high carrier concentrations. The strategies to suppress the carrier concentrations have also been addressed, such as ultra-high vacuum conditions and low temperature growth.