Fig. 1. The schematic diagram of the a-Ga₂O₃ MSM SBPD (left) and its microscopic image (right)

Fig. 2. (a) GIXRD spectra of the substrate and a-Ga₂O₃ film deposited at pure Ar; (b) XPS survey of a-Ga₂O₃ film deposited at pure Ar

Fig. 3. Optical transmittance spectra of a-Ga₂O₃ films deposited at different oxygen partial pressures and (αhν)²-hν plots(inset)

Fig. 4. XPS O 1s core level and fitting results of a-Ga₂O₃ films under different oxygen partial pressures. (a) O 1s core level of a-Ga₂O₃ films with different oxygen partial pressures; Fitting results of O 1s core level of (b) pure Ar, (c) 3% oxygen partial pressure, and(d) 7% oxygen partial pressure

Fig. 5. The current-voltage(I-V) of the a-Ga₂O₃ MSM SBPDs under different oxygen partial pressures. (a) The dark current characteristics and the responsivity under three conditions(inset); (b) The photocurrent characteristics(254 nm, 80 μW/cm²)

Fig. 6. Transient responses of a-Ga₂O₃ MSM SBPDs under different oxygen partial pressures. (a) Transient response for multicycles; (b) Normalized transient response; Experimental and fitted curves of the rise and decay processes for the device with (c) 3% oxygen partial pressure and (d) 7% oxygen partial pressure