Synthesis and characterization of multi-phase structure, optical and electrical properties on (Ga–Sn) oxide composite thin film by sol-gel method

Abstract

The structural and optical properties of the films were investigated as a function of increasing high Gallium content amounts in the range 10–30 mol %. The composite thin films were characterized by crystallography, surface morphology, optical and electrical properties. The X-ray diffraction (XRD) method revealed that the composited thin films were multiphase in rutile tetragonal (SnO2) and β phase monoclinic (Ga2O3) type crystal structure with grown strongly in the (200) and (4‾ 01), respectively. In addition, for comparative investigate the effect of high concentration Ga incorporation on the lattice of SnO2 and the mechanism for lattice strain, Williamson-Hall method introduced. The surface morphology was investigated by Field emission Scanning Electron Microscope (FE-SEM) measurement, and it confirmed that crystallite size difference and multi-phase appear with high Ga incorporated. With UV–vis spectrometer, all (Ga–Sn) oxide composite thin films revealed a transparency of approximately 78% in the visible region. For comparative analysis of the band gap of the composite thin film, the estimated value was derived from Tauc plot, and the measured value was investigated by photoluminescence (PL). The electrical sheet resistance was measured by four-point probe method and optimized sheet resistance value of 5.66 kΩ/sq when the mixture of Ga 20 mol % concentration.