MBE growth of 2H-MoTe2 and 1T'-MoTe2 on 3D substrates

Abstract

MoTe2 is the least explored material in the Molybdenum-chalcogen family, which crystallizes in thermodynamically stable semiconducting 2H phase at \textless 500 C and 1T' metallic phase at higher temperatures. Molecular beam epitaxy (MBE) provides an unique opportunity to tackle the small electronegativity difference between Mo and Te while growing layer by layer away from thermodynamic equilibrium. For a few-layer MoTe2 grown at a moderate rate of $\sim$6 mins per monolayer under varied Te:Mo flux ratio and substrate temperature, the boundary between the 2 phases in MBE grown MoTe2 on CaF2 is characterized using Reflection high-energy electron diffraction (RHEED), Raman spectroscopy and X-ray photoemission spectroscopy (XPS). Grazing incidence X-ray diffraction (GI-XRD) reveals a grain size of $\sim$90 Å and presence of twinned grains. XRD, transmission electron miscroscopy, RHEED, low energy electron diffraction along with lack of electrical conductivity modulation by field effect in MBE 2H-MoTe2 on GaAs (111) B show likelihood of excess Te incorporation in the films. Finally, thermal stability and air sensitivity of MBE 2H-MoTe2 is investigated by temperature dependent XRD and XPS, respectively.

Six figure in main tex, 8 figures in SI and 4 tables in main text

References in corpus (5)

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Cited by in corpus (5)

• Experimental Progress on Layered Topological Semimetals
• Variability and Reliability of Graphene Field-Effect Transistors with CaF2 Insulators
• Electronic structure of molecular beam epitaxy grown 1T${}^{\prime }$-MoTe${}_2$ film and strain effect
• Photoluminescence efficiency of MBE-grown MoSe${}_2$ monolayers featuring sharp excitonic lines and diverse grain structures
• Epitaxy of new layered materials: 2D chalcogenides and challenges of weak van der Waals interactions