Resonant tunnelling into the two-dimensional subbands of InSe layers

Zakhar R Kudrynskyi,Debarati Mazumder,Mark T Greenaway,Oleg Makarovsky,Zakhar D Kovalyuk,Peter H Beton,Laurence Eaves,Amalia Patanè,James Kerfoot,Evgeni E Vdovin

doi:10.1038/s42005-020-0290-x

Abstract

Two-dimensional (2D) van der Waals (vdW) crystals have attracted considerable interest for digital electronics beyond Si-based complementary metal oxide semiconductor technologies. Despite the transformative success of Si-based devices, there are limits to their miniaturization and functionalities. Here we realize a resonant tunnelling transistor (RTT) based on a 2D InSe layer sandwiched between two multilayered graphene (MLG) electrodes. In the RTT the energy of the quantum-confined 2D subbands of InSe can be tuned by the thickness of the InSe layer. By applying a voltage across the two MLG electrodes, which serve as the source and drain electrodes to the InSe, the chemical potential in the source can be tuned in and out of resonance with a given 2D subband, leading to multiple regions of negative differential conductance that can be additionally tuned by electrostatic gating. This work demonstrates the potential of InSe and InSe-based RTTs for applications in quantum electronics.

Highlights

Two-dimensional (2D) van der Waals crystals have attracted considerable interest for digital electronics beyond Si-based complementary metal oxide semiconductor technologies
Heterostructures based on two-dimensional (2D) van der Waals crystals[1,2,3], such as graphene, hexagonal boron nitride, and metal mono- (e.g., InSe, GaSe...) and di-chalcogenide (e.g., SnSe2, MoS2...) layers have physical properties that may overcome some of the technological limitations of traditional covalent semiconductors[4]
Beyond their versatility for a wide range of band structure-engineered devices by stacking and/or twisting the layers, these structures can be readily transferred onto substrates that are compatible with the well-established complementary metal–oxide–semiconductor (CMOS) device fabrication processes used in modern integrated circuits for digital logic, image sensors and transceivers

Summary

Introduction

Two-dimensional (2D) van der Waals (vdW) crystals have attracted considerable interest for digital electronics beyond Si-based complementary metal oxide semiconductor technologies. Different types of tunnel field effect transistors (TFET) based on vdW crystals have emerged, stimulating research of fundamental and applied interest[5,6,7,8,9,10,11,12,13] These devices include the graphene/insulator/graphene TFET with a region of negative differential conductance (NDC) in the current–voltage characteristics due to resonant tunnelling[8]. We report on a different type of TFET, a resonant tunneling transistor (RTT), which exhibits multiple regions of NDC These device structures exploit the tunnelling of charge carriers from a source of electrons into the distinct 2D subband states of an InSe vdW crystal a few atomic layers thick. InSe offers exciting possibilities for these technological developments due to its high room temperature electron mobility and its tuneable band gap and energy subbands[14,15,16]

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Results

Conclusion