Salt-Assisted Selective Growth of H-phase Monolayer VSe<sub>2</sub> with Apparent Hole Transport Behavior
Jiawen You, Jie Pan, Shun‐Li Shang, Xiang Xu, Zhenjing Liu, Jingwei Li, Hongwei Liu, Ting Kang, Mengyang Xu, Shaobo Li, Deqi Kong, Wenliang Wang, Zhaoli Gao, Xing Zhou, Tianyou Zhai, Zi‐Kui Liu, Jang‐Kyo Kim, Zhengtang Luo
Abstract
Vanadium diselenide (VSe2) 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 VSe2 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 VSe2 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 p-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.