Growth and Thermo-driven Crystalline Phase Transition of Metastable Monolayer 1T'-WSe2 Thin Film

Abstract

Two-dimensional (2D) transition metal dichalcogenides MX2 (M = Mo, W, X = S, Se, Te) attracts enormous research interests in recent years. Its 2H phase possesses an indirect to direct bandgap transition in 2D limit, and thus shows great application potentials in optoelectronic devices [1]. The 1T' crystalline phase transition can drive the monolayer MX2 to be a 2D topological insulator. Here we realized the molecular beam epitaxial (MBE) growth of both the 1T' and 2H phase monolayer WSe2 on bilayer graphene (BLG) substrate. The crystalline structures of these two phases were characterized using scanning tunneling microscopy. The monolayer 1T'-WSe2 was found to be metastable, and can transform into 2H phase under post-annealing procedure. The phase transition temperature of 1T'-WSe2 grown on BLG is lower than that of 1T' phase grown on 2H-WSe2 layers. This thermo-driven crystalline phase transition makes the monolayer WSe2 to be an ideal platform for the controlling of topological phase transitions in 2D materials family.

References in corpus (23)

• Quantum Spin Hall Effect in Graphene
• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Quantum Spin Hall Effect in Silicene
• Quantum Spin Hall Effect
• Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides
• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Direct observation of the transition from indirect to direct bandgap in atomically thin epitaxial MoSe2
• Large-gap quantum spin Hall insulators in tin films
• Phonon and Raman scattering of two-dimensional transition metal dichalcogenides from monolayer, multilayer to bulk material
• Lattice dynamics in mono- and few-layer sheets of WS2 and WSe2
• Realization of Quantum Spin Hall State in Monolayer 1T'-WTe2
• Observation of the Quantum Spin Hall Effect up to 100 Kelvin in a Monolayer Crystal
• Experimental observation of topological Fermi arcs in type-II Weyl semimetal MoTe2
• Quantum Spin Hall Effect and Enhanced Magnetic Response by Spin-Orbit Coupling
• Prediction of the Weyl semimetal in the orthorhombic MoTe2
• Observation of charge density wave order in 1D mirror twin boundaries of single-layer MoSe2
• Spectroscopic Evidence of Type II Weyl Semimetal State in WTe2
• Observation of Large Topologically Trivial Fermi-Arcs in the Candidate Type-II Weyl Semimetal WTe2
• Electronic Structure, Surface Doping, and Optical Response in Epitaxial WSe2 Thin Films
• Rotationally Commensurate Growth of MoS2 on Epitaxial Graphene
• Quantum-spin-Hall insulator with a large gap: single-layer 1T' WSe${}_2$
• Observation of Topologically Protected States at Crystalline Phase Boundaries in Single-layer WSe2
• Observation of Coulomb gap in the quantum spin Hall candidate single-layer 1T'-WTe${}_2$

Cited by in corpus (4)

• Signature of large-gap quantum spin Hall state in the layered mineral jacutingaite
• Phase evolution and superconductivity enhancement in Se-substituted MoTe${}_2$ thin films
• Thermal Stability of Hafnium Zirconium Oxide on Transition Metal Dichalcogenides
• Robust Coulomb Gap and Varied-temperature Study of Epitaxial 1T'-WSe${}_2$ Monolayers