Tunable Ga<sub>2</sub>O<sub>3</sub> solar-blind photosensing performance via thermal reorder engineering and energy-band modulation
Zhaoying Xi, Sihan Yan, Zeng Liu, Lili Yang, Maolin Zhang, Yufeng Guo, Weihua Tang
Abstract
Abstract As an ultra-wide bandgap semiconductor, gallium oxide (Ga 2 O 3 ) has been extensively applied in solar-blind photodetectors (PDs) owing to the absorbance cut-off wavelength of shorter than 280 nm, and the optimized technologies of detection performance is seriously essential for its further usages. Herein, a feasible thermal reorder engineering method was performed through annealing Ga 2 O 3 films in vacuum, O 2 and oxygen plasma atmospheres, realizing to tune solar-blind photosensing performance of Ga 2 O 3 PDs. Thermal treatment, in fact a crystal reorder process, significantly suppressed the noise in Ga 2 O 3 -based PDs and enhanced the photo-sensitivity, with the dark current decreasing from 154.63 pA to 269 fA and photo-to-dark current ratio magically raising from 288 to 2.85 × 10 4 . This achievement is dependent of energy-band modulation in Ga 2 O 3 semiconductor, that is certified by first-principles calculation. Additionally, annealing in oxygen atmospheres notably reduces the concentration of oxygen vacancies in the surface of films, thereby improving the performance of the PDs; the oxygen vacancy is extremely concerned in oxide semiconductors in the view of physics of surface defects. In all, this work could display a promising guidance for modulating the performance of PDs based on wide bandgap oxide semiconductor, especially for hot Ga 2 O 3 issue.