High-Performance Solar-Blind Ultraviolet Photodetectors Based on a Ni/β-Ga₂O₃ Vertical Schottky Barrier Diode

Abstract

Ga₂O₃ Schottky photodiodes are being actively explored for solar-blind ultraviolet (SBUV) detection, owing to the fast photoresponse and easy fabrication. However, their performance, limited by the Schottky contact, mostly underperforms the expectations. Herein, a Ni/β-Ga₂O₃ vertical Schottky barrier diode (SBD) with an ultrathin anode electrode is demonstrated. Through simple surface treatment, the quality of the Schottky junction is improved, thus the detection performance. The dark current reaches a record of less than 12 fA. Benefiting from this, an ultrahigh photo-to-dark current ratio (PDCR) of 4.92 × 10⁷ and specific detectivity D* of 2.76 × 10¹⁵ Jones are achieved. The response time is also reduced to the order of milliseconds. The experimental result shows that the device still works properly at a high temperature of 150 °C. Most importantly, the fabricated photodetectors have good uniformity and operational stability. Our results provide a simple approach to mass produce high-performance Ga₂O₃ photodetectors, holding tremendous potential for UV imaging applications.