Tunable Ambipolar Polarization-Sensitive Photodetectors Based on High-Anisotropy ReSe2 Nanosheets

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• 作者：Enze Zhang ; Peng Wang ; Zhe Li ; Haifeng Wang ; Chaoyu Song ; Ce Huang ; Zhi-Gang Chen ; Lei Yang ; Kaitai Zhang ; Shiheng Lu ; Weiyi Wang ; Shanshan Liu ; Hehai Fang ; Xiaohao Zhou ; Hugen Yan ; Jin Zou ; Xiangang Wan ; Peng Zhou ; Weida Hu ; Faxian Xiu
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：August 23, 2016
• 年：2016
• 卷：10
• 期：8
• 页码：8067-8077
• 全文大小：890K
• 年卷期：0
• ISSN：1936-086X

文摘

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 10⁷ 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.