【Device Papers】Tailoring surface properties and optoelectronic response of Ga₂O₃ films through advanced surface state engineering

      Researchers from the Changchun University of Science and Technology have published a dissertation titled "Tailoring surface properties and optoelectronic response of Ga₂O₃ films through advanced surface state engineering" in Applied Surface Science.

Abstract

      The performance of β-Ga₂O₃-based metal–semiconductor-metal (MSM) solar-blind photodetectors is limited by the high density of oxygen vacancy (V_O) defects on their surface, which leads to high dark current and slow photoresponse. Here, this study proposes a plasma surface treatment strategy to enhance photodetector performance through controllable modulation of surface defects. A comparative analysis of the effects of O₂, N₂, and Ar plasmas on the surface characteristics and optoelectronic properties of β-Ga₂O₃ films elucidates the defect modulation mechanisms and identifies an effective pathway for optimizing device performance. Specifically, O₂ and N₂ plasma treatments reduced the V_O concentration from 34.62 % in the untreated sample to 20.47 % and 21.79 %, respectively, thereby significantly suppressing the dark current and the persistent photoconductivity (PPC) effect. In contrast, the Ar plasma treatment, through physical sputtering, increased the V_O concentration to 53.17 %. This introduction of surface defects reduces the metal–semiconductor contact resistance and enhances light absorption, which in turn optimizes the photocurrent and response speed. The Ar plasma-treated photodetector exhibited the best performance, achieving a responsivity (R) of 141 mA/W, a detectivity (D*) of 2.6 × 10¹¹ Jones, and fast rise/decay times of 3.07 s/2.06 s, which is a significant improvement over the untreated photodetector (7.09 s/8.42 s).

DOI：

https://doi.org/10.1016/j.apsusc.2025.165035