Salt-Assisted Selective Growth of H-phase Monolayer VSe<sub>2</sub> with Apparent Hole Transport Behavior.

You, Jiawen; Pan, Jie; Shang, Shun-Li; Xu, Xiang; Liu, Zhenjing; Li, Jingwei; Liu, Hongwei; Kang, Ting et al. · Nano Lett · 2022

basic_science · Level V

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Abstract

Vanadium diselenide (VSe<sub>2</sub>) exhibits versatile electronic and magnetic properties in the trigonal prismatic (H-) and octahedral (T-) phases. Compared to the metallic T-phase, the H-phase with a tunable semiconductor property is predicted to be a ferrovalley material with spontaneous valley polarization. Herein we report an epitaxial growth of the monolayer 2D VSe<sub>2</sub> on a mica substrate via the chemical vapor deposition (CVD) method by introducing salt in the precursor. Our first-principles calculations suggest that the monolayer H-phase VSe<sub>2</sub> with a large lateral size is thermodynamically favorable. The honeycomb-like structure and the broken symmetry are directly observed by spherical aberration-corrected scanning transmission electron microscopy (STEM) and confirmed by giant second harmonic generation (SHG) intensity. The <i>p</i>-type transport behavior is further evidenced by the temperature-dependent resistance and field-effect device study. The present work introduces a new phase-stable 2D transition metal dichalcogenide, opening the prospect of novel electronic and spintronics device design.