A flexible and transparent β-Ga2O3solar-blind ultraviolet photodetector on mica

In the present work, we report a flexible transparent beta-Ga2O3 solar-blind ultraviolet (UV) photodetector (PD) fabricated on a mica substrate. A laminated a-Ga2O3/Ga/a-Ga2O3 structure is thermally annealed at 1050 degrees C, forming a beta-Ga2O3 film incorporating Ga nanospheres. A PD based on this nanocomposite film has a spectrum response peak at 250 nm, an extremely low dark current of 0.6 pA at a 10 V bias, a very high I-light/I(dark)ratio of 3 x 10(6), and a fast recovery speed of less than 50 ms. Robust flexibility is demonstrated by bending tests and 10 000 cycles of a fatigue test with a radius as small as 8 mm. Compared to a room-temperature-fabricated flexible amorphous Ga2O3(a-Ga2O3) PD, the flexible beta-Ga2O3PD on mica exhibits improved solar-blind UV photoresponse characteristics. The insertion of a gallium interlayer and treatment by high-temperature post annealing are proposed to contribute to a better stoichiometry and lattice order of the beta-Ga(2)O(3)thin film, as evidenced by the pronounced Raman peaks related to the Ga-I(O-I)(2) and GaIO4 vibration modes in beta-phase Ga2O3. Our research is believed to provide a simple and practical route to achieving flexible transparent beta-Ga2O3 solar-blind UV PDs, as well as other devices such as flexible transparent phototransistors and power rectifiers.