Photoluminescence properties of α-(Al <i>x</i> Ga1– <i>x</i> )2O3 thin films under excitation with synchrotron radiation

α-(AlxGa1−x)2O3 has great potential in deep ultraviolet (DUV) optoelectronic devices due to its ultra-wide bandgap. The α-(AlxGa1−x)2O3 films demonstrated good DUV photodetection but hardly exhibited luminescence in the DUV range. To date, no reports on the luminescence properties of α-(AlxGa1−x)2O3 have been published. In this work, the photoluminescence properties of α-(AlxGa1−x)2O3 thin films from DUV to the red region at a low temperature of 40 K were systematically studied using synchrotron radiation. Based on our observations, some intriguing features have been discussed. The strong emission of α-(AlxGa1−x)2O3 in the DUV region is dominated by two bands with peaks at 239 and 258 nm. This work indicates α-(AlxGa1−x)2O3 films are potential DUV light-emitting materials.