High Electron Mobility, Quantum Hall Effect and Anomalous Optical Response in Atomically Thin InSe

Abstract

A decade of intense research on two-dimensional (2D) atomic crystals has revealed that their properties can differ greatly from those of the parent compound. These differences are governed by changes in the band structure due to quantum confinement and are most profound if the underlying lattice symmetry changes. Here we report a high-quality 2D electron gas in few-layer InSe encapsulated in hexagonal boron nitride under an inert atmosphere. Carrier mobilities are found to exceed 1,000 and 10,000 cm2/Vs at room and liquid-helium temperatures, respectively, allowing the observation of the fully-developed quantum Hall effect. The conduction electrons occupy a single 2D subband and have a small effective mass. Photoluminescence spectroscopy reveals that the bandgap increases by more than 0.5 eV with decreasing the thickness from bulk to bilayer InSe. The band-edge optical response vanishes in monolayer InSe, which is attributed to monolayer's mirror-plane symmetry. Encapsulated 2D InSe expands the family of graphene-like semiconductors and, in terms of quality, is competitive with atomically-thin dichalcogenides and black phosphorus.

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• Electrons and phonons in single layers of hexagonal indium chalcogenides from ab initio calculations
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Cited by in corpus (19)

• Recent progress in the assembly of nanodevices and van der Waals heterostructures by deterministic placement of 2D materials
• Observation of ballistic avalanche phenomena in nanoscale vertical InSe/BP heterostructures
• Electronic and optical properties of two-dimensional InSe from a DFT-parameterized tight-binding model
• One-dimensional phosphorus chain and two-dimensional blue phosphorene grown on Au(111) by molecular-beam epitaxy
• Indirect to direct gap crossover in two-dimensional InSe revealed by ARPES
• Atomic-scale mechanisms of defect- and light-induced oxidation and degradation of InSe
• Theoretical realization of Mo2P, a novel stable 2D material with superionic conductivity and attractive optical properties
• van der Waals Bonded Co/h-BN Contacts to Ultrathin Black Phosphorus Devices
• Environmental Stability of Bismuthene: Oxidation Mechanism and Structural Stability of 2D Pnictogens
• Drastic enhancement of the Raman intensity in few-layer InSe by uniaxial strain
• Spin-orbit coupling, optical transitions, and spin pumping in mono- and few-layer InSe
• Hot Carrier and Surface Recombination Dynamics in Layered InSe Crystals
• Strong Modulation of Optical Properties in Rippled 2D GaSe via Strain Engineering
• Evidence of Direct Electronic Band Gap in two-dimensional van der Waals Indium Selenide crystals
• Emergence of Dirac-like bands in the monolayer limit of epitaxial Ge films on Au(111)
• Ultrasensitive Tunability of the Direct Bandgap of Two-dimensional InSe Flakes via Strain Engineering
• Pressure-controlled Structural Symmetry Transition in Layered InSe
• Theoretical insight into the interaction of O2 and H2O molecules with the perfect and the defective InSe monolayers
• Dirac Material Graphene