A high-performance ultraviolet solar-blind photodetector based on a β-Ga2O3 Schottky photodiode

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2019, Vol.7 (44), p.13920-13929
• Main Authors: Liu, Zeng, Wang, Xia, Liu, Yuanyuan, Guo, Daoyou, Li, Shan, Yan, Zuyong, Chee-Keong Tan, Li, Wanjun, Li, Peigang, Tang, Weihua
• Format: Article
• Language: English
• Subjects: Biological evolution; Dark current; Earth surface; Energy conservation; Energy consumption; Gallium oxides; Magnetron sputtering; Photodiodes; Photometers; Quantum efficiency; Sapphire; Selectivity; Substrates; Ultraviolet detectors; Ultraviolet radiation
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c9tc04912f

UV ray detection near the earth surface has become urgent due to the serious effects of UV rays on human health, the environment and the biological evolution; therefore, the development of energy-saving UV photodetectors with high responsivity, specific detectivity, and sensitivity is urgently desired. Herein, we fabricated a lateral β-Ga2O3 Schottky photodiode on a sapphire substrate via magnetron sputtering using Ti and Ni as ohmic and Schottky contacts, respectively. The photodiode shows rectifying behaviors in the dark and under 254/365 nm UV light illuminations. As a photodetector, it exhibits the high photo-to-dark current ratio of 2.83 × 105 owing to its low dark current (1.32 × 10−11 A) and strong UV absorbance. The responsivity at 250 nm could reach up to 144.46 A W−1 at 10 V. The external quantum efficiency of 64 711% and the ideal specific detectivity of 7.29 × 1014 cm Hz1/2 W−1 (Jones) were also achieved. The rejection ratio (R250 nm/R400 nm) was as high as 4.8 × 103, suggesting high wavelength selectivity. The responsivity of 2301.78 A W−1 at 180 V proves the ability of this photodetector to operate at high voltages. In addition, it can operate with the responsivity of 0.73 mA W−1 and the specific detectivity of 3.35 × 1010 cm Hz1/2 W−1 (Jones) at zero bias. Overall, the lateral Ti/β-Ga2O3/Ni structured Schottky photodiode was verified as an excellent candidate for UV solar-blind detection with high performance and low energy consumption.