【Epitaxy Papers】Optimized oxygen flux in sputtering amorphous Ga₂O₃ thin films enables high-performance solar-blind UV photodetectors

       Researchers from the Xi’an Jiaotong University have published a dissertation titled "Optimized oxygen flux in sputtering amorphous Ga₂O₃ thin films enables high-performance solar-blind UV photodetectors" in Vacuum.

Abstract

       This study systematically investigates the effect of oxygen flux on the optical properties of amorphous gallium oxide (a-Ga₂O₃) thin films deposited on SiO₂/Si substrates via RF magnetron sputtering. Through comprehensive material characterization and device performance analysis, we elucidate the correlation between defect evolution (including oxygen vacancies and other intrinsic defects) and the resulting optoelectronic responses. Our findings reveal that oxygen vacancy concentration mainly influences the optical band gap. Although increasing oxygen flux significantly reduces the oxygen vacancy concentration, the overall defect density exhibits a nonlinear trend because additional defect states are concurrently introduced. Consequently, the device performance exhibits a nonlinear dependence on oxygen flux. The detector prepared under moderate oxygen flux conditions exhibits an ultra-high light-dark current ratio of up to 4×10⁵ and a low dark current at the pA level. Furthermore, these devices demonstrate rapid response kinetics, with a rise time of 28.9 ms and a fall time of 0.9 ms. These changes are attributed to the interplay between defects and material properties. This study provides critical insights into the process development of high-performance a-Ga₂O₃ solar-blind UV photodetectors.

DOI：

https://doi.org/10.1016/j.vacuum.2025.114748