Fig. 1. (a) Schematic representation of the device; (b) XRD result for a-Ga₂O₃/paper sample; a-Ga₂O₃/Al₂O₃ and paper substrate XRD results are also displayed for comparison.

Fig. 2. (a) XPS survey spectrum of the as-grown a-Ga₂O₃ thin film; (b) core level of Ga 2p. (c) core level of O 1s; (d) UV-VIS absorbance spectrum of the a-Ga₂O₃ thin film with the plot of (αhν)² versus hν in the inset.

Fig. 3. (a) I-V characteristic of the Au/Ti-a-Ga₂O₃-Ti/Au structure, with inset showing the photograph of the flexible PDs; (b) I-V characteristic curves of the Ga₂O₃ PD in the dark and under 254 nm light illumination with various light intensities; (c) current as a function of the light intensity under a voltage bias of 10 V; (d) spectral response of PD.

Fig. 4. (a) Responsivity and detectivity of the PDs at various light intensities; (a) PDCR and EQE of the PDs at various light intensities.

Fig. 5. (a) Temporal photoresponse of the detector at 10 V bias under 254 nm illuminations with different light intensities; response time of the device under 254 nm illuminations with (b) 10 µW/cm², (c) 100 µW/cm², and (d) 1000 µW/cm².

Fig. 6. (a) I-V characteristics of the a-Ga₂O₃ flexible PD with various twisting angles at fixed illumination; the inset is the digital image of the experimental setup. (b) I-V characteristics of the PD with different bending radii, with photographic image of the bending device before optoelectronic test in the inset; (c) time-dependence of the device for different bendings applied; (d) performance degradation of the photodetector as a function of the number of bending cycles at a bending radius of 8 mm.