【Epitaxy Papers】Synergistically enhancing solar-blind UV photodetection performance of β-Ga₂O₃ thin films by Al₂O₃ interfacial passivation and Fowler–Nordheim tunneling

      Researchers from Liaoning Normal University have published a dissertation titled " Synergistically enhancing solar-blind UV photodetection performance of β-Ga₂O₃ thin films by Al₂O₃ interfacial passivation and Fowler–Nordheim tunneling " in Physica B: Condensed Matter.

Abstract

      Ultrawide-bandgap β-Ga₂O₃ has emerged as a promising platform for solar-blind ultraviolet (UV) detection, yet its performance is often hindered by surface defects and inefficient carrier transport. Here, we report a systematic interface-engineering strategy employing ultrathin Al₂O₃ passivation layers to enhance the optoelectronic response of sputtered Ga₂O₃ thin films. Transparent indium tin oxide (ITO) interdigitated electrodes were integrated to construct MISIM-type photodetectors, enabling efficient light coupling while mitigating metal-induced absorption. The optimized device with a 5 nm Al₂O₃ layer achieves a high photo-to-dark current ratio of 1.2 × 10⁶, an external quantum efficiency of 5110%, a responsivity of 10.45 A/W, a specific detectivity of 4.5 × 10¹³ Jones, and a solar-blind suppression ratio of 2400. Unlike conventional approaches where dark current suppression dominates, the observed performance enhancement primarily arises from a significant photocurrent gain. Mechanistic analysis reveals that Al₂O₃ passivation simultaneously suppresses interface states, modulates interfacial band structure, and facilitates Fowler–Nordheim tunneling and impact ionization, leading to efficient carrier separation and multiplication. This work highlights the critical role of interfacial chemistry and dielectric engineering in overcoming intrinsic limitations of β-Ga₂O₃, offering valuable insights for the design of next-generation high-performance solar-blind UV photodetectors.

DOI：

https://doi.org/10.1016/j.physb.2026.419034