Tunnel spectroscopy of localised electronic states in hexagonal boron nitride

Abstract

Hexagonal boron nitride (hBN) is a large band gap layered crystal, frequently incorporated in van der Waals (vdW) heterostructures as an insulating or tunnel barrier. Localised states with energies within its band gap can emit visible light, relevant to applications in nanophotonics and quantum information processing. However, they also give rise to conducting channels, which can induce electrical breakdown when a large voltage is applied. Here we use gated tunnel transistors to study resonant electron tunnelling through the localised states in few atomic-layer hBN barriers sandwiched between two monolayer graphene electrodes. The measurements are used to determine the energy, linewidth, tunnelling transmission probability, and depth within the barrier of more than 50 distinct localised states. A three-step process of electron percolation through two spatially separated localised states is also investigated.

Supplementary information can be found at https://doi.org/10.1038/s42005-018-0097-1

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• Zeeman tunability of Andreev bound states in van-der-Waals tunnel barriers
• Spectroscopy of $NbS{e}_2$ using Energy-Tunable Defect-Embedded Quantum Dots
• Electrical Charge Control of h-BN Single Photon Sources
• Quantum-Dot Assisted Spectroscopy of Degeneracy-Lifted Landau Levels in Graphene
• Semiconductor channel mediated photodoping in h-BN encapsulated monolayer MoSe2 phototransistors
• Twisted monolayer and bilayer graphene for vertical tunneling transistors
• Tunneling spectroscopy of localized states of ${\mathrm{WS}}_2$ barriers in vertical van der Waals heterostructures
• Tunneling Spectroscopy of Two-Dimensional Materials Based on Via Contacts
• A magnetically-induced Coulomb gap in graphene due to electron-electron interactions
• Step-directed Epitaxy of Uni-directional Hexagonal Boron Nitride on Vicinal Ge(110)
• Imaging the Sub-Moiré Potential Landscape using an Atomic Single Electron Transistor
• Kondo Effect in Defect-bound Quantum Dots Coupled to NbSe${}_2$