Ra, Hyun-Soo Ahn, Jongtae Jang, Jisu TAEWOOK, KIM Song, Seung Ho Jeong, Min-Hye Lee, Sang-Hyeon Yoon, Taegeun Yoon, Tea Woong Kim, Seungsoo Taniguch, Takashi Watanabe, Kenji Song, Young Jae Lee, Jong-Soo Hwang, Do Kyung 2024-01-19T12:34:19Z 2024-01-19T12:34:19Z 2022-02-17 2022-02 0935-9648 https://pubs.kist.re.kr/handle/201004/115686 The probing of fundamental photophysics is a key prerequisite for the construction of diverse optoelectronic devices and circuits. To date, though, photocarrier dynamics in 2D materials remains unclear, plagued primarily by two issues: a large exciton binding energy, and the lack of a suitable system that enables the manipulation of excitons. Here, a WSe2-based phototransistor with an asymmetric split-gate configuration is demonstrated, which is named the "asymmetry field-effect phototransistor" (AFEPT). This structure allows for the effective modulation of the electric-field profile across the channel, thereby providing a standard device platform for exploring the photocarrier dynamics of the intrinsic WSe2 layer. By controlling the electric field, this work the spatial evolution of the photocurrent is observed, notably with a strong signal over the entire WSe2 channel. Using photocurrent and optical spectroscopy measurements, the physical origin of the novel photocurrent behavior is clarified and a room-temperature exciton binding energy of 210 meV is determined with the device. In the phototransistor geometry, lateral p-n junctions serve as a simultaneous pathway for both photogenerated electrons and holes, reducing their recombination rate and thus enhancing photodetection. The study establishes a new device platform for both fundamental studies and technological applications. English WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim An Asymmetry Field-Effect Phototransistor for Solving Large Exciton Binding Energy of 2D TMDCs Article 10.1002/adma.202107468 1 Advanced Materials, v.34, no.7 Advanced Materials 34 7 N scie scopus 000740655700001 2-s2.0-85122680715 Chemistry, Multidisciplinary Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Physics, Condensed Matter Chemistry Science & Technology - Other Topics Materials Science Physics Article LAYER MOS2 WSE2 GAIN WS2 asymmetry exciton dynamics field-effect transistors phototransistors WSe (2)