Flexible fast responding solar-blind photodetectors based on (TmGa)2O3 films grown on mica

As an ultra-wide bandgap semiconductor, gallium oxide (Ga2O3) holds great application potential in deep-ultraviolet (DUV) photodetectors. While the performance of photodetectors based on crystalline Ga2O3 thin films grown on hard substrates has been continuously improved, photodetectors based on amorphous Ga2O3 grown on less-stringent substrates in a more convenient and accessible way emerged as alternative technology and received increasing attention. Herein, we choose thulium (Tm) for doping and grow amorphous Tm-Ga2O3 films on non-lattice-matched flexible mica substrates. Thanks to the larger bandgap of Tm2O3 (∼6.5 eV) and stronger Tm–O bond, the (TmxGa1−x)2O3 films possess broadened bandgap and lessened oxygen vacancies compared to pure Ga2O3. Consequently, the photodetectors that were produced based on these amorphous (TmxGa1−x)2O3 films exhibit high performances with both low dark current and fast response speed (36.47 pA and 0.07 s at x = 0.05) and well maintain the performance after multiple cycles of bending at radius as small as 5 mm. This work sheds light on the development of flexible devices based on amorphous (TmxGa1−x)2O3 for solar-blind DUV detection.