Zn2SbN3: growth and characterization of a metastable photoactive semiconductor

Abstract

Ternary nitride semiconductors with wurtzite-derived crystal structures are an emerging class of materials for optoelectronic applications compatible with GaN and related III–V compounds. In particular, II–IV–V₂ materials such as ZnSnN₂ and ZnGeN₂ have been very actively studied for applications in photovoltaics and light emitting devices. However, many other possible wurtzite-derived ternary nitrides have not been reported, and hence their optical and electrical properties remain unknown. Here, we report on Zn₂SbN₃ – the first Sb-based nitride and a photoactive semiconductor. Surprisingly, Zn₂SbN₃ contains Sb in the highest (5+) oxidation state, and in the unusual tetrahedral coordination. This new Zn₂SbN₃ material has a solar-matched 1.6–1.7 eV band gap and shows near-band-edge room-temperature photoluminescence, demonstrating its promise as an optoelectronic semiconductor. Finally, Zn₂SbN₃ can be synthesized at low temperature under a wide range of processing conditions, despite being metastable according to theoretical calculations. All these results, as well as the band position measurements, indicate that Zn₂SbN₃ is a promising emerging semiconductor for applications as an absorber in photovoltaic- and photoelectrochemical solar cells.