# Millimeter-scale layered MoSe2 grown on sapphire and evidence for negative magnetoresistance

## TL;DR

This study demonstrates scalable growth of millimeter-scale layered MoSe2 on sapphire, revealing negative magnetoresistance and carrier hopping behavior, indicating intrinsic charge transport properties in 2D materials at large scales.

## Contribution

It provides the first evidence of negative magnetoresistance in millimeter-scale MoSe2, showing that such properties are intrinsic and scalable in 2D layered materials.

## Key findings

- Negative magnetoresistance observed at millimeter scale
- Carrier transport follows two-dimensional variable range hopping
- Scalable growth of MoSe2 on sapphire confirmed

## Abstract

Molecular beam epitaxy technique has been used to deposit a single layer and a bilayer of MoSe 2 on sapphire. Extensive characterizations including in-situ and ex-situ measurements show that the layered MoSe 2 grows in a scalable manner on the substrate and reveals characteristics of a stoichiometric 2H-phase. The layered MoSe 2 exhibits polycrystalline features with domains separated by defects and boundaries. Temperature and magnetic field dependent resistivity measurements unveil a carrier hopping character described within two-dimensional variable range hopping mechanism. Moreover, a negative magnetoresistance was observed, stressing a fascinating feature of the charge transport under the application of a magnetic field in the layered MoSe 2 system. This negative magnetoresistance observed at millimeter-scale is similar to that observed recently at room temperature inWS2 flakes at a micrometer scale [Zhang et al., Appl. Phys. Lett. 108, 153114 (2016)]. This scalability highlights the fact that the underlying physical mechanism is intrinsic to these two-dimensional materials and occurs at very short scale.

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Source: https://tomesphere.com/paper/1702.05121