Preparation and Characterization of Radio Frequency Sputtered Delafossite p-type Copper Gallium Oxide (p-CuGaO2) Thin Films

Abstract

In this research, CuGaO2 thin films were prepared on quartz substrates by radio frequency magnetron sputtering technique at 400 °C followed by subsequent annealing in N2 ambiance. The effects of annealing temperature on structural, morphological, optical, and electrical properties of CuGaO2 thin films are reported in this work. X-ray Diffraction (XRD) analysis confirmed the presence of single-phase CuGaO2 in the film annealed at 900 °C. Near stoichiometric composition ratio of Cu:Ga (1:1.08) was identified in the film annealed at 900 °C. The Field Emission Scanning Electron Microscope (FESEM) images showed an increase in the grain size with an increase in annealing temperature. A UV–V is spectrophotometer was used to perform optical studies in the 200–800 nm wavelength region on all films. The optical bandgap was calculated from the transmission studies and was found to be in the range of 2.77 to 3.43 eV. The films annealed at temperatures 800 °C and above were found to be p-type. The lowest resistivity value of 230 Ω-cm was achieved in the film annealed at 900 °C.