Stacking-Order-Driven Optical Properties and Carrier Dynamics in ReS2 |
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Authors: | Yongjian Zhou Nikhilesh Maity Amritesh Rai Rinkle Juneja Xianghai Meng Anupam Roy Yanyao Zhang Xiaochuan Xu Jung-Fu Lin Sanjay K. Banerjee Abhishek K. Singh Yaguo Wang |
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Affiliation: | 1. Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712 USA;2. Materials Research Centre, Indian Institute of Science, Bangalore, 560012 India;3. Microelectronics Research Center, The University of Texas at Austin, Austin, TX, 78758 USA;4. Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, 78712 USA;5. State Key Laboratory on Tunable Laser Technology, Harbin Institute of Technology, Shenzhen, Guangdong, 518055 China;6. Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, 78712 USA Texas Materials Institute, The University of Texas at Austin, Austin, TX, 78712 USA |
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Abstract: | Two distinct stacking orders in ReS2 are identified without ambiguity and their influence on vibrational, optical properties and carrier dynamics are investigated. With atomic resolution scanning transmission electron microscopy (STEM), two stacking orders are determined as AA stacking with negligible displacement across layers, and AB stacking with about a one-unit cell displacement along the a axis. First-principles calculations confirm that these two stacking orders correspond to two local energy minima. Raman spectra inform a consistent difference of modes I & III, about 13 cm−1 for AA stacking, and 20 cm−1 for AB stacking, making a simple tool for determining the stacking orders in ReS2. Polarized photoluminescence (PL) reveals that AB stacking possesses blueshifted PL peak positions, and broader peak widths, compared with AA stacking, indicating stronger interlayer interaction. Transient transmission measured with femtosecond pump–probe spectroscopy suggests exciton dynamics being more anisotropic in AB stacking, where excited state absorption related to Exc. III mode disappears when probe polarization aligns perpendicular to b axis. The findings underscore the stacking-order driven optical properties and carrier dynamics of ReS2, mediate many seemingly contradictory results in the literature, and open up an opportunity to engineer electronic devices with new functionalities by manipulating the stacking order. |
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Keywords: | 2D materials carrier dynamics first-principles calculations optical properties pump–probe ReS2 |
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