Semiconducting ZnSnxGe1−xN2 alloys prepared by reactive radio-frequency sputtering

We report on the fabrication and structural and optoelectronic characterization of II-IV-nitride ZnSnxGe1−xN2 thin-films. Three-target reactive radio-frequency sputtering was used to synthesize non-degenerately doped semiconducting alloys having <10% atomic composition (x = 0.025) of tin. These low-Sn alloys followed the structural and optoelectronic trends of the alloy series. Samples exhibited semiconducting properties, including optical band gaps and increasing in resistivities with temperature. Resistivity vs. temperature measurements indicated that low-Sn alloys were non-degenerately doped, whereas alloys with higher Sn content were degenerately doped. These films show potential for ZnSnxGe1−xN2 as tunable semiconductor absorbers for possible use in photovoltaics, light-emitting diodes, or optical sensors.