Electrodeposition of Ga–O Thin Films from Aqueous Gallium Sulfate Solutions

Ga–O based thin films were electrodeposited on fluorine-doped tin oxide (FTO)-coated glass substrate at room temperature from aqueous gallium sulfate solution with hydrogen peroxide (H₂O₂). Effects of different deposition parameters such as deposition voltage, amount of H₂O₂ and deposition time were investigated and presented. Nearly smooth and crack-free morphologies were attained at -1.0 V vs SCE deposition potential. As-deposited films showed O to Ga ratio of 2.0, which signified GaOOH formation. Thermal annealing of the as-deposited films in ambient air at 500–600 °C reduced the O/Ga ratio closer to stoichiometric gallium oxide (Ga₂O₃) and retained the morphology of Ga–O thin films. As-prepared films with ∼0.2 µm thickness had 80% transparency in the visible wavelength range.