title: Tunable Ambipolar Polarization-Sensitive Photodetectors Based on High-Anisotropy ReSe2 Nanosheets.
abstract: Atomically thin 2D-layered transition-metal dichalcogenides have been studied extensively in recent years because of their intriguing physical properties and promising applications in nanoelectronic devices. Among them, ReSe2 is an emerging material that exhibits a stable distorted 1T phase and strong in-plane anisotropy due to its reduced crystal symmetry. Here, the anisotropic nature of ReSe2 is revealed by Raman spectroscopy under linearly polarized excitations in which different vibration modes exhibit pronounced periodic variations in intensity. Utilizing high-quality ReSe2 nanosheets, top-gate ReSe2 field-effect transistors were built that show an excellent on/off current ratio exceeding 10(7) and a well-developed current saturation in the current-voltage characteristics at room temperature. Importantly, the successful synthesis of ReSe2 directly onto hexagonal boron nitride substrates has effectively improved the electron motility over 500 times and the hole mobility over 100 times at low temperatures. Strikingly, corroborating with our density-functional calculations, the ReSe2-based photodetectors exhibit a polarization-sensitive photoresponsivity due to the intrinsic linear dichroism originated from high in-plane optical anisotropy. With a back-gate voltage, the linear dichroism photodetection can be unambiguously tuned both in the electron and hole regime. The appealing physical properties demonstrated in this study clearly identify ReSe2 as a highly anisotropic 2D material for exotic electronic and optoelectronic applications.
authors.forename: Enze
authors.initials: E
authors.lastname: Zhang
authors.affiliation: National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences , Shanghai 200083, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.forename: Zhe
authors.initials: Z
authors.lastname: Li
authors.forename: Haifeng
authors.initials: H
authors.lastname: Wang
authors.forename: Chaoyu
authors.initials: C
authors.lastname: Song
authors.forename: Ce
authors.initials: C
authors.lastname: Huang
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: Chen
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
authors.forename: Kaitai
authors.initials: K
authors.lastname: Zhang
authors.forename: Shiheng
authors.initials: S
authors.lastname: Lu
authors.forename: Weiyi
authors.initials: W
authors.lastname: Wang
authors.forename: Shanshan
authors.initials: S
authors.lastname: Liu
authors.affiliation: National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences , Shanghai 200083, China.
authors.forename: Hehai
authors.initials: H
authors.lastname: Fang
authors.affiliation: National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences , Shanghai 200083, China.
authors.forename: Xiaohao
authors.initials: X
authors.lastname: Zhou
authors.forename: Hugen
authors.initials: H
authors.lastname: Yan
authors.forename: Jin
authors.initials: J
authors.lastname: Zou
authors.forename: Xiangang
authors.initials: X
authors.lastname: Wan
authors.forename: Peng
authors.initials: P
authors.lastname: Zhou
authors.affiliation: National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences , Shanghai 200083, China.
authors.forename: Weida
authors.initials: W
authors.lastname: Hu
authors.forename: Faxian
authors.initials: F
authors.lastname: Xiu
keywords: ReSe2; ambipolar; anisotropy; linear dichroism photodetection