Jeong Tae Young, Kim Hakseong, Choi Sang-Jun, Watanabe Kenji, Taniguchi Takashi, Yee Ki Ju, Kim Yong-Sung, Jung Suyong
Quantum Technology Institute, Korea Research Institute of Standards and Science, Daejeon, 34113, Korea.
Department of Physics, Chungnam National University, Daejeon, 34134, Korea.
Nat Commun. 2019 Aug 23;10(1):3825. doi: 10.1038/s41467-019-11751-3.
Assessing atomic defect states and their ramifications on the electronic properties of two-dimensional van der Waals semiconducting transition metal dichalcogenides (SC-TMDs) is the primary task to expedite multi-disciplinary efforts in the promotion of next-generation electrical and optical device applications utilizing these low-dimensional materials. Here, with electron tunneling and optical spectroscopy measurements with density functional theory, we spectroscopically locate the mid-gap states from chalcogen-atom vacancies in four representative monolayer SC-TMDs-WS, MoS, WSe, and MoSe-, and carefully analyze the similarities and dissimilarities of the atomic defects in four distinctive materials regarding the physical origins of the missing chalcogen atoms and the implications to SC-mTMD properties. In addition, we address both quasiparticle and optical energy gaps of the SC-mTMD films and find out many-body interactions significantly enlarge the quasiparticle energy gaps and excitonic binding energies, when the semiconducting monolayers are encapsulated by non-interacting hexagonal boron nitride layers.
评估二维范德华半导体过渡金属二硫属化物（SC-TMDs）中的原子缺陷态及其对电子性质的影响，是加快多学科研究步伐以推动利用这些低维材料的下一代电气和光学器件应用的首要任务。在此，通过电子隧穿和光学光谱测量以及密度泛函理论，我们通过光谱定位了四种代表性单层SC-TMDs（WS、MoS、WSe和MoSe）中硫属原子空位的带隙中间态，并仔细分析了四种不同材料中原子缺陷在缺失硫属原子的物理起源以及对SC-mTMD性质的影响方面的异同。此外，我们研究了SC-mTMD薄膜的准粒子和光学能隙，发现当半导体单层被非相互作用的六方氮化硼层封装时，多体相互作用会显著扩大准粒子能隙和激子结合能。
