The effect of crystal quality on persistent photoconductivity in β -Ga2O3 photodetectors

Gallium oxide (Ga2O3) thin films were prepared using the metal organic chemical vapor deposition method, and photoconductive photodetectors were constructed. The results showed that with the increase in growth temperature, the grain size of Ga2O3 increased and the surface smoothness improved significantly. The full width at half maxima of the rocking curve decreases with the increase in growth temperature, indicating an improvement in crystal quality. The photoluminescence spectra of all films extend from ultraviolet (UV) to visible light. The responsivity of the fabricated photoconductive devices exceeds 5 A/W, with a maximum detectivity reaching ∼2 × 1015 Jones. The photoresponse spectrum is located in the solar-blind UV range, exhibiting excellent spectral selectivity. All devices exhibit significant photoconductive relaxation phenomena. The variations of these parameters are related to self-trapped holes (STHs) and defect-trapped holes within the material. Since STHs are an inherent characteristic of oxide semiconductors, they cannot be completely eliminated. The persistent photoconductivity effect can only be eliminated through external excitation.