Phase-Controlled Growth of One-Dimensional Mo₆Te₆ Nanowires and Two-Dimensional MoTe₂ Ultrathin Films Heterostructures.

Abstract

Controllable synthesizing of one-dimensional-two-dimensional (1D-2D) heterostructures and tuning their atomic and electronic structures is nowadays of particular interest due to the extraordinary properties and potential applications. Here, we demonstrate the temperature-induced phase-controlled growth of 1D Mo₆Te₆-2D MoTe₂ heterostructures via molecular beam epitaxy. In situ scanning tunneling microscopy study shows 2D ultrathin films are synthesized at low temperature range, while 1D nanowires gradually arise and dominate as temperature increasing. X-ray photoelectron spectroscopy confirms the good stoichiometry and scanning tunneling spectroscopy reveals the semimetallic property of grown Mo₆Te₆ nanowires. Through in situ annealing, a phase transition from 2D MoTe₂ to 1D Mo₆Te₆ is induced, thus forming a semimetal-semiconductor junction in atomic level. An upward band bending of 2H-MoTe₂ is caused by lateral hole injection from Mo₆Te₆. The work suggests a new route to synthesize 1D semimetallic transition metal chalcogenide nanowires, which could serve as ultrasmall conducting building blocks and enable band engineering in future 1D-2D heterostructure devices.