Investigation OfThe Effect Of Gallium (Ga) On Properties Of Zinc Oxide (ZnO) Thin Films Prepared By Spray Pyrolysis Technique

Thin films of zinc oxide (ZnO) and gallium (Ga) doped zinc oxide (GZO) were successfully deposited on a glass substrate using spray pyrolysis technique at a temperature of 350 °C. Surface morphological, structural, optical, and electrical properties of the ZnO films are investigated as a function of different doping concentrations of Ga, ranging from 0 to 5%. Based on X-ray diffraction analysis, it is observed that the ZnO film exhibits the polycrystalline hexagonal (wurtzite) crystal structure. The film have orientations along various planes, including (100), (002), (101), (102), (110), (103), and (112). The morphological spectrograph reveals that the ZnO films exhibit a unique nanorope-like morphology, which undergoes changes upon Ga doping. According to the energy dispersive x-ray spectroscopy study, Zn and O are present in ZnO films, while Zn, O, and Ga ions are present in Ga-doped films. The optical transmittance across a wide range of wavelengths, from 300 to 1100 nm has been examined. There is a noticeable trend in the optical transmittance and optical band gap of ZnO thin film with increasing Ga doping concentration. Initially, both values increase by up to 4%, but then they start to decrease. The electrical resistivity decreases to 2.94 × 10^{− 2} (ohm-cm), compared to the initial value of 4.56 × 10^{− 2} (ohm-cm) when the ZnO thin film is doped with 4% Ga.