Properties of RF Magnetron-Sputtered Copper Gallium Oxide (CuGa2O4) Thin Films

Abstract

Thin films of CuGa2O4 were deposited using an RF magnetron-sputtering technique for the first time. The sputtered CuGa2O4 thin films were post-deposition annealed at temperatures varying from 100 to 900 °C in a constant O2 ambience for 1.5 h. Structural and morphological studies were performed on the films using X-ray diffraction analysis (XRD) and a Field Emission Scanning Electron Microscope (FESEM). The presence of CuGa2O4 phases along with the CuO phases was confirmed from the XRD analysis. The minimum critical temperature required to promote the crystal growth in the films was identified to be 500 °C using XRD analysis. The FESEM images showed an increase in the grain size with an increase in the annealing temperature. The resistivity values of the films were calculated to range between 6.47 × 103 and 2.5 × 108 Ωcm. Optical studies were performed on all of the films using a UV-Vis spectrophotometer. The optical transmission in the 200–800 nm wavelength region was noted to decrease with an increase in the annealing temperature. The optical bandgap value was recorded to range between 3.59 and 4.5 eV and showed an increasing trend with an increase in the annealing temperature.

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

“…A similar optical transmission value was reported in films annealed at 700 °C in O 2 ambiance, which comprised of CuGa 2 O 4 and CuO phases. 28 However, further increase in annealing temperature resulted in higher transmission values, which is characteristic of films having majorly CuGaO 2 phases. 22,29,30 The films annealed at 800 °C and 900 °C exhibited transmission values of close to 60% at 500 nm.…”

Annealing Studies of Copper Indium Oxide (Cu2In2O5) Thin Films Prepared by RF Magnetron Sputtering

“…An early attempt to synthesize a p-type TCO from CuAlO 2 by the laser ablation method was reported by Kawazoe et al [13]. Recently, researchers have been looking at the copper indium oxide-and copper gallium oxide-based thin film materials for possible p-type TCO applications [14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Nair et al fabricated a transparent thin-film p-n junction consisting of Ca and tin-doped CuInO 2 [28].…”

Preparation and Characterization of p-Type Copper Gallium Oxide (CuGaO2) Thin Films by Dual Sputtering Using Cu and Ga2O3 Targets

“…RF magnetron sputtering technique provides the flexibility to choose the source target materials, regulate the film thickness and deposition rate, and provides thin films with greater adhesion over a large surface area. 25 Unlike CVD, magnetron sputtering does not demand the use of toxic precursors.…”