High-performance solar-blind deep ultraviolet photodetector based on the H2-annealed amorphous ZnGa2O4 and its preliminary exploration in image sensor

The development of solar-blind ultraviolet detectors urgently requires amorphous semiconductor materials with a sufficiently wide bandgap, environment-friendly, and low fabrication costs. In this work, amorphous ZnGa2O4 films were grown by magnetron sputtering, and the effect of H2 thermal annealing on the changes of microstructure and macroscopic physical properties of the materials was systematically investigated. The passivation of oxygen vacancy after H2 annealing allows the photodetector (PD) constructed by the amorphous ZnGa2O4 film to be highly sensitive to 228 nm deep ultraviolet illumination with exceptional photoresponse behaviors. Under the deep UV light with 29.38 μW/cm2 irradiation at 228 nm, the photo-to-dark current ratio (PDCR), responsivity (R), detectivity (D*), response speed, and UV-visible rejection ratio (Rpeak/R400 nm) were as high as 2.37 × 106, 15.15 A/W, 2.35 × 1013 Jones, 0.20/0.21 s, and 2.46 × 106, respectively. In addition, the PD based on H2-annealed ZnGa2O4 still exhibits a high PDCR of ∼103 under extremely minimal light intensity irradiation. This PD can sensitively record a brief “FJ” image generated by deep UV light. This work provides a feasible method for the construction of high-performance optoelectronic devices and systems based on amorphous ZnGa2O4.