Tunable 2H–TaSe_2 room-temperature terahertz photodetector  

作　　者：Jin Wang Cheng Guo Wanlong Guo Lin Wang Wangzhou Shi Xiaoshuang Chen 王瑾;郭程;郭万龙;王林;石旺舟;陈效双(Department of Physics Shanghai Normal University;State Key Laboratory for Infrared Physics Shanghai Institute of Technical Physics Chinese Academy of Sciences;University of Chinese Academy of Sciences)

机构地区：[1]Department of Physics Shanghai Normal University [2]State Key Laboratory for Infrared Physics Shanghai Institute of Technical Physics Chinese Academy of Sciences [3]University of Chinese Academy of Sciences

出　　处：《Chinese Physics B》2019年第4期18-22,共5页中国物理B（英文版）

基　　金：Project supported by the State Key Basic Research Program of China(Grant Nos.2017YFA0205801,2017YFA0305500,and 2013CB632705);the National Natural Science Foundation of China(Grant Nos.11334008,61290301,61521005,61405230,and 61675222);the Youth Innovation Promotion Association(CAS);the Aviation Science Fund(Grant No.20162490001)

摘　　要：Two-dimensional transition metal dichalcogenides(TMDs) provide fertile ground to study the interplay between dimensionality and electronic properties because they exhibit a variety of electronic phases, such as semiconducting, superconducting, charge density waves(CDW) states, and other unconventional physical properties. Compared with other classical TMDs, such as Mott insulator 1T–TaS_2 or superconducting 2H–NbSe_2, bulk 2H–TaSe_2 has been a canonical system and a touchstone for modeling the CDW measurement with a less complex phase diagram. In contrast to ordinary semiconductors that have only single-particle excitations, CDW can have collective excitation and carry current in a collective fashion. However, manipulating this collective condensation of these intriguing systems for device applications has not been explored. Here, the CDW-induced collective driven of non-equilibrium carriers in a field-effect transistor has been demonstrated for the sensitive photodetection at the highly-pursuit terahertz band. We show that the 2H–TaSe_2-based photodetector exhibits a fast photoresponse, as short as 14 μs, and a responsivity of over 27 V/W at room temperature. The fast response time, relative high responsivity and ease of fabrication of these devices yields a new prospect of exploring CDW condensate in TMDs with the aim of overcoming the existing limitations for a variety of practical applications at THz spectral range.Two-dimensional transition metal dichalcogenides(TMDs) provide fertile ground to study the interplay between dimensionality and electronic properties because they exhibit a variety of electronic phases, such as semiconducting, superconducting, charge density waves(CDW) states, and other unconventional physical properties. Compared with other classical TMDs, such as Mott insulator 1T–TaS_2 or superconducting 2H–NbSe_2, bulk 2H–TaSe_2 has been a canonical system and a touchstone for modeling the CDW measurement with a less complex phase diagram. In contrast to ordinary semiconductors that have only single-particle excitations, CDW can have collective excitation and carry current in a collective fashion. However, manipulating this collective condensation of these intriguing systems for device applications has not been explored. Here, the CDW-induced collective driven of non-equilibrium carriers in a field-effect transistor has been demonstrated for the sensitive photodetection at the highly-pursuit terahertz band. We show that the 2H–TaSe_2-based photodetector exhibits a fast photoresponse, as short as 14 μs, and a responsivity of over 27 V/W at room temperature. The fast response time, relative high responsivity and ease of fabrication of these devices yields a new prospect of exploring CDW condensate in TMDs with the aim of overcoming the existing limitations for a variety of practical applications at THz spectral range.

关 键 词：TERAHERTZ detection transition metal DICHALCOGENIDES PHOTOCONDUCTIVE 

分 类 号：O441.4[理学—电磁学] TN15[理学—物理]