Abstract:Amorphous Ga2O3 (a-Ga2O3) thin films were prepared on flexible polyimide, rigid quartz glass, and Si substrates via radio frequency magnetron sputtering at room temperature. The effect of oxygen/Ar flow rate ratio on the structure, optical property, surface morphology, and chemical bonding properties of the a-Ga2O3 films was investigated. Results show that the average optical transmittance of the a-Ga2O3 films is over 80% within the wavelength range of 300–2000 nm. The extracted optical band gap of the a-Ga2O3 films is increased from 4.97 eV to 5.13 eV with the increase in O2/Ar flow rate ratio from 0 to 0.25, due to the decrease in concentration of oxygen vacancy defects in the film. Furthermore, the optical refractive index and surface roughness of the a-Ga2O3 films are optimized when the O2/Ar flow rate ratio reaches 0.25. X-ray photoelectron spectroscopy analysis also shows that the proportion of oxygen vacancies (VO) and Ga-O chemical bonds in the O 1s peak is gradually decreased with the increase in O2/Ar flow rate ratio from 0 to 0.25, proving that increasing the O2/Ar flow rate ratio during film growth can reduce the concentration of oxygen vacancy defects in a-Ga2O3 films. In this case, a-Ga2O3 with optimal properties can be obtained. This work provides a research basis for high-performance flexible and rigid deep ultraviolet solar-blind detection devices based on a-Ga2O3 films.