Thermal annealing impact on crystal quality of (GaIn)2O3 alloys

• Phase separation and thermal annealing effects on the (GaIn)2O3 films were studied.
• Phase separation were observed when substrate temperature is higher than 300 °C.
• Thermal annealing the film resulted in (GaIn)2O3 film without phase separation.

In this study, we investigated the phase separation phenomenon and post thermal annealing effects on the (GaIn)2O3 films deposited on sapphire substrates by pulsed laser deposition. Films grown at substrate temperature higher than 300 °C showed phase separation while films grown at substrate temperature lower than 200 °C revealed homogenous elements distributions with amorphous structure. Thermal annealing had no obvious effects on (GaIn)2O3 films grown at substrate temperature higher than 300 °C. The clusters remained on the surface of the films after thermal annealing treatment. On the other hand, however, by thermal annealing the film deposited at room temperature, (GaIn)2O3 film with smooth surface, homogenous element distribution, high orientation crystal and high optical transmittance observed by means of scanning electron microscope, energy dispersive spectrometer, X-ray diffraction and spectrophotometer was successfully obtained, paving a way for obtaining high quality (GaIn)2O3 film without phase separation.