【Device Papers】Sol-gel synthesized Ga₂O₃/InGaO heterojunction-based MSM Solar-Blind photodetector with ohmic contacts for high-performance UV detection

      Researchers from the Jilin University have published a dissertation titled "Sol-gel synthesized Ga₂O₃/InGaO heterojunction-based MSM Solar-Blind photodetector with ohmic contacts for high-performance UV detection" in Journal of Alloys and Compounds.

Abstract

      As a representative wide bandgap semiconductor material, β-Ga₂O₃ demonstrates significant potential for solar-blind ultraviolet (UV) photodetection applications, with its performance being further optimizable through strategic material engineering. In this study, an MSM solar-blind UV photodetector (PD) based on a Ga₂O₃/InGaO heterojunction (GIH) was fabricated. Incorporating indium (In) into the Ga₂O₃ lattice to form InGaO (IGO) elevates the Fermi level and introduces self-capturing holes, improving electronic properties and leading to high-gain photoconductivity. The inherent built-in electric field, originating from a coupled depletion-accumulation space charge region at the heterojunction interface, effectively suppresses majority carrier transport by inducing a substantial energy barrier, thereby achieving superior dark current suppression under dark conditions. Furthermore, the interfacial engineering between Au electrodes and the IGO surface establishes an ohmic contact configuration, which ensures efficient collection and unimpeded transport of photo-generated carriers without transport barrier. The results reveal that the GIH UVPD demonstrated a notable light current of 2.2 mA and a low dark current of 0.72 nA at 5 V bias, leading to an impressively high photo-to-dark current ratio of 6 orders of magnitude (3.06×10⁶). Under consistent bias conditions, the GIH UVPD achieves remarkable spectral-selectivity performance, exhibiting a pronounced responsivity of 1.72×10⁴ A/W at 260 nm through enhanced photoconductive gain mechanisms, accompanied by an exceptional UV/visible rejection ratio (R_260nm/R_400nm) of 7.54×10³, and achieving an ultrahigh detectivity of 5.71×10¹⁵ Jones attributed to effective dark current suppression. This research presents a promising approach for fabricating high-performance solar-blind UVPDs.

DOI：

https://doi.org/10.1016/j.jallcom.2026.186094