Structural and Electrical Properties of MoTe$_2$ and MoSe$_2$ Grown by Molecular Beam Epitaxy

TL;DR

This paper reports the successful growth and characterization of MoTe2 and MoSe2 thin films on sapphire using molecular beam epitaxy, revealing their structural, chemical, and electrical properties.

Contribution

It introduces a method for growing high-quality layered MoTe2 and MoSe2 films with detailed structural and electrical analysis, advancing 2D material fabrication techniques.

Findings

Stoichiometric layered film growth confirmed

Crystalline 2H phase observed via Raman spectroscopy

Electrical behavior follows a 2D variable-range hopping model

Abstract

We demonstrate the growth of thin films of molybdenum ditelluride and molybdenum diselenide on sapphire substrates by molecular beam epitaxy. In-situ structural and chemical analyses reveal stoichiometric layered film growth with atomically smooth surface morphologies. Film growth along the (001) direction is confirmed by X-ray diffraction, and the crystalline nature of growth in the 2H phase is evident from Raman spectroscopy. Transmission electron microscopy is used to confirm the layered film structure and hexagonal arrangement of surface atoms. Temperature dependent electrical measurements show an insulating behavior which agrees well with a two-dimensional variable-range hopping model, suggesting that transport in these films is dominated by localized charge-carrier states.