# Highly-Oriented Atomically Thin Ambipolar MoSe$_2$ Grown by Molecular Beam Epitaxy

## TL;DR

This paper demonstrates the growth of high-quality, atomically thin MoSe2 using molecular beam epitaxy on GaAs substrates, enabling ambipolar transport and detailed analysis of its electrical properties.

## Contribution

It introduces a method for large-area, highly aligned MBE-grown MoSe2 with controllable crystalline orientation and demonstrates ambipolar transport in these films.

## Key findings

- No intermediate compounds at the interface.
- Highly aligned films with two crystalline orientations.
- Ambipolar transport achieved via polymer electrolyte gating.

## Abstract

Transition metal dichalcogenides (TMDCs), together with other two-dimensional (2D) materials have attracted great interest due to the unique optical and electrical properties of atomically thin layers. In order to fulfill their potential, developing large-area growth and understanding the properties of TMDCs have become crucial. Here, we used molecular beam epitaxy (MBE) to grow atomically thin MoSe$_2$ on GaAs(111)B. No intermediate compounds were detected at the interface of as-grown films. Careful optimization of the growth temperature can result in the growth of highly aligned films with only two possible crystalline orientations due to broken inversion symmetry. As-grown films can be transferred onto insulating substrates allowing their optical and electrical properties to be probed. By using polymer electrolyte gating, we have achieved ambipolar transport in MBE-grown MoSe$_2$. The temperature-dependent transport characteristics can be explained by the 2D variable-range hopping (2D-VRH) model, indicating that the transport is strongly limited by the disorder in the film.

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Source: https://tomesphere.com/paper/1705.10563