Flexible fast responding solar-blind photodetectors based on (TmGa)2O3 films grown on mica
Qiulin Qu, Qi Liu, Lufeng Chen, Yingxiang Li, Hang Pan, Jian Chen, Mingkai Li, Yinmei Lu, Yunbin He
Abstract
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.