Optical Properties of Gallium Oxide Thin Films

We report studies conducted on gallium oxide films deposited using magnetron sputtering from a 99.9\% pure ceramic target on sapphire substrates. Conditions varied were the process gas using different mixtures of argon/oxygen (0/100, 20/80, 50/50, 80/20 and 100/0), substrate temperature (20 $^o$C to 850 $^o$C) and film thickness (140 nm $\textendash$ 860 nm). The films were analyzed by UV-VIS spectrometry, x-ray diffraction and energy dispersive x-ray spectroscopy measurements. The optical measurements revealed high transmission of 92\%- 95\% and optical bandgaps of 4.4 – 4.9 eV. Data from the x-ray diffraction on the film deposited at 850 $^o$C showed a characteristic peak at 18$^o$ for the oxide material.