title: Zero-Power-Consumption Solar-Blind Photodetector Based on β-Ga2O3/NSTO Heterojunction.
abstract: A solar-blind photodetector based on β-Ga2O3/NSTO (NSTO = Nb:SrTiO3) heterojunctions were fabricated for the first time, and its photoelectric properties were investigated. The device presents a typical positive rectification in the dark, while under 254 nm UV light illumination, it shows a negative rectification, which might be caused by the generation of photoinduced electron-hole pairs in the β-Ga2O3film layer. With zero bias, that is, zero power consumption, the photodetector shows a fast photoresponse time (decay time τd= 0.07 s) and the ratio Iphoto/Idark≈ 20 under 254 nm light illumination with a light intensity of 45 μW/cm2. Such behaviors are attributed to the separation of photogenerated electron-hole pairs driven by the built-in electric field in the depletion region of β-Ga2O3and the NSTO interface, and the subsequent transport toward corresponding electrodes. The photocurrent increases linearly with increasing the light intensity and applied bias, while the response time decreases with the increase of the light intensity. Under -10 V bias and 45 μW/cm2of 254 nm light illumination, the photodetector exhibits a responsivity Rλof 43.31 A/W and an external quantum efficiency of 2.1 × 104%. The photo-to-electric conversion mechanism in the β-Ga2O3/NSTO heterojunction photodetector is explained in detail by energy band diagrams. The results strongly suggest that a photodetector based on β-Ga2O3thin-film heterojunction structure can be practically used to detect weak solar-blind signals because of its high photoconductive gain.
authors.affiliation: Center for Optoelectronics Materials and Devices, Department of Physics, Zhejiang Sci-Tech University , Hangzhou 310018, China.|State Key Laboratory of Information Photonics and Optical Communications & Laboratory of Optoelectronics Materials and Devices, School of Science, Beijing University of Posts and Telecommunications , Beijing 100876, China.
authors.forename: Daoyou
authors.initials: D
authors.lastname: Guo
authors.affiliation: Center for Optoelectronics Materials and Devices, Department of Physics, Zhejiang Sci-Tech University , Hangzhou 310018, China.
authors.forename: Han
authors.initials: H
authors.lastname: Liu
authors.affiliation: Center for Optoelectronics Materials and Devices, Department of Physics, Zhejiang Sci-Tech University , Hangzhou 310018, China.|State Key Laboratory of Information Photonics and Optical Communications & Laboratory of Optoelectronics Materials and Devices, School of Science, Beijing University of Posts and Telecommunications , Beijing 100876, China.
authors.forename: Peigang
authors.initials: P
authors.lastname: Li
authors.affiliation: State Key Laboratory of Information Photonics and Optical Communications & Laboratory of Optoelectronics Materials and Devices, School of Science, Beijing University of Posts and Telecommunications , Beijing 100876, China.
authors.forename: Zhenping
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Center for Optoelectronics Materials and Devices, Department of Physics, Zhejiang Sci-Tech University , Hangzhou 310018, China.
authors.forename: Shunli
authors.initials: S
authors.lastname: Wang
authors.affiliation: Center for Optoelectronics Materials and Devices, Department of Physics, Zhejiang Sci-Tech University , Hangzhou 310018, China.
authors.forename: Can
authors.initials: C
authors.lastname: Cui
authors.affiliation: Center for Optoelectronics Materials and Devices, Department of Physics, Zhejiang Sci-Tech University , Hangzhou 310018, China.
authors.forename: Chaorong
authors.initials: C
authors.lastname: Li
authors.affiliation: Center for Optoelectronics Materials and Devices, Department of Physics, Zhejiang Sci-Tech University , Hangzhou 310018, China.|State Key Laboratory of Information Photonics and Optical Communications & Laboratory of Optoelectronics Materials and Devices, School of Science, Beijing University of Posts and Telecommunications , Beijing 100876, China.
authors.forename: Weihua
authors.initials: W
authors.lastname: Tang
keywords: photodetector; rectification; solar blind; thin film; zero power consumption; β-Ga2O3/NSTO heterojunction