High-performance photodetector based on sol-gel epitaxially grown α/β Ga2O3 thin films

Abstract Ga 2 O 3 has been receiving more and more attention for solar blind photodetectors due to it has a large direct bandgap corresponding to solar blind waveband. However, numerous photodetectors based on single crystalline Ga 2 O 3 exhibited a relatively large dark current and a low photo-to-dark current ratio. Herein,the α / β phase polycrystalline Ga 2 O 3 thin film was successfully synthesized via sol-gel method and the photodetector with low dark current(18.5 pA at 15 V) and high photo-to-dark current ratio(1664) was further fabricated. By optimizing annealing environment, the photodetector also exhibited an excellent detectivity ( D * ) of 5.41 × 10 11 Jones and a fast photo-response speed (a rise time of 0.03 s/0.23 s and a decay time of 0.04 s/0.41 s). Excellent performance can be ascribed to that tailoring of the defect concentration in the polycrystalline Ga 2 O 3 film by introducing α -Ga 2 O 3 into β -Ga 2 O 3 and the physical mechanism was discussed with a carrier transport model. The experimental results suggested the great potential applications of Ga 2 O 3 thin films synthesized by the sol-gel method in ultraviolet detection and our experiment reveals an effective method for manufacturing high-performance solar-blind photodetectors.