Electron transport mechanism in rf-sputtered amorphous zinc oxynitride thin films

We discuss the carrier transport mechanism in amorphous zinc oxynitride (ZnON) thin films fabricated by means of long-throw magnetron sputtering. ZnON films were radio-frequency sputtered from a metallic zinc target in a reactive atmosphere consisting of and Ar. The electrical conductivity of the films was controlled via variation of the deposition pressure and substrate temperature. Room temperature deposition yields amorphous, n-type semiconducting ZnON thin films with a maximum Hall mobility of and carrier concentrations of . The mobility can be further increased up to the range by moderate substrate heating or annealing up to while maintaining the amorphous phase. From temperature-dependent Hall effect measurements, we deduced that a percolation conduction model is most likely for the electron transport in the as-grown ZnON thin films. For annealed samples, a quasi-metallic behavior is observed. (C) 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim