Resonant Tunneling in Tri-layer 2H-MoTe2 grown by Molecular Beam Epitaxy Coupled with layered WSe2 carrier Reservoir

TL;DR

This paper demonstrates quantum oscillations in a MoTe2-based resonant tunneling device fabricated via MBE and CVD, revealing size-dependent tunneling behavior and a record peak-to-valley ratio at cryogenic temperatures.

Contribution

It reports the first observation of resonant tunneling in MoTe2 devices with detailed analysis of quantum well width effects and high PVR, advancing 2D material-based tunneling technology.

Findings

Quantum oscillations observed in MoTe2 RTD at cryogenic temperatures.

Peak-to-valley ratio of 4 achieved at 4K in MoTe2 RTD.

Resonant tunneling current depends on quantum well width.

Abstract

Here, we report a prominent quantum oscillation in the conductance of 2H-MoTe2 based resonant tunneling structure. In this work, a n-WSe2/HfO2/i-MoTe2/HfO2/Au resonant tunneling device (RTD) with a symmetric and asymmetric double barrier has been fabricated using Molecular Beam Epitaxy (MBE) grown 2H-MoTe2 and Chemical Vapor Deposition (CVD) grown 2H-WSe2 along with theoretical modeling by adopting non-equilibrium Green function (NEGF) formalism. The impact of MoTe2-quantum well widths equal, and above its excitonic Bohr radius (EBR:0.7 nm) on resonant tunneling current is investigated at cryogenic temperatures. Such peak values increase with downscaling of the well width up to a certain value and then it decreases with further miniaturization. The corresponding maximum peak-to-valley current ratio (PVR) is estimated to be 4 at 4K in the low voltage range for the very first time in MoTe2 based RTD. Therefore, the present work may provide the route for fabrication of WSe2/MoTe2-based high performance resonant tunneling devices integrable with HEMT device for modern Qubit architecture operational at ultra-low temperatures.