Epitaxial Synthesis of Monolayer PtSe<sub>2</sub> Single Crystal on MoSe<sub>2</sub> with Strong Interlayer Coupling.

Zhou, Jiadong; Kong, Xianghua; Sekhar, M Chandra; Lin, Junhao; Le Goualher, Frederic; Xu, Rui; Wang, Xiaowei; Chen, Yu et al. · ACS Nano · 2019

basic_science · Level V

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Abstract

PtSe<sub>2</sub>, a layered two-dimensional transition-metal dichalcogenide (TMD), has drawn intensive attention owing to its layer-dependent band structure, high air stability, and spin-layer locking effect which can be used in various applications for next-generation optoelectronic and electronic devices or catalysis applications. However, synthesis of PtSe<sub>2</sub> is highly challenging due to the low chemical reactivity of Pt sources. Here, we report the chemical vapor deposition of monolayer PtSe<sub>2</sub> single crystals on MoSe<sub>2</sub>. The periodic Moiré patterns from the vertically stacked heterostructure (PtSe<sub>2</sub>/MoSe<sub>2</sub>) are clearly identified <i>via</i> annular dark-field scanning transmission electron microscopy. First-principles calculations show a type II band alignment and reveal interface states originating from the strong-weak interlayer coupling (SWIC) between PtSe<sub>2</sub> and MoSe<sub>2</sub> monolayers, which is supported by the electrostatic force microscopy imaging. Ultrafast hole transfer between PtSe<sub>2</sub> and MoSe<sub>2</sub> monolayers is observed in the PtSe<sub>2</sub>/MoSe<sub>2</sub> heterostructure, matching well with the theoretical results. Our study will shed light on the synthesis of Pt-based TMD heterostructures and boost the realization of SWIC-based optoelectronic devices.