Probing the Valley-Selective Tunneling Density of States in Monolayer MoS2 based Resonant Tunneling Devices

TL;DR

This paper demonstrates the fabrication and analysis of monolayer MoS2 resonant tunneling devices, revealing valley-specific electronic states, multiple resonant peaks, and high PVR values, with implications for quantum technology.

Contribution

It introduces a novel monolayer MoS2 RTD architecture compatible with CMOS technology, combining experimental and theoretical insights into valley-specific tunneling phenomena.

Findings

Multiple resonant tunneling peaks observed in I-V characteristics.

High PVR values of 178 at 4K and 24 at room temperature.

Valley-specific electronic states influenced by S-vacancies and doping.

Abstract

The present work experimentally demonstrates the fabrication of CVD grown monolayer MoS2 ultra thin quantum well based double barrier resonant tunneling device (RTD) architecture well compatible with conventional CMOS fabrication technology. The strongly quantized electronic states from multiple valleys in the momentum space in such ultra 2D sheet along the c-axis sandwiched in between Al2O3 tunneling barriers exhibit multiple resonant tunneling peaks thereby enhancing the FWHM of the NDR region as derived from experimental I-V characteristics as well as theoretical joint invision through Density Functional Theory (DFT) and Non-Equilibrium Greens function (NEGF) visualized via Tunneling Density of States (TDOS). Understanding extended to S-vacancies not only change the bandgap, as evaluated through nanoscale Cathodoluminescence (CL) spectroscopy, but also alters the effective mass hence the mobility as investigated here within the high symmetry path in the k-space. Electrical performances of fabricated RTD, starting from cryogenic to room temperatures, show a significant milestone via exhibiting huge PVR values of 178 at 4K and 24 at RT with more possible improvement in the field of room temperature quantum technology. Momentum conserved and non conserved tunneling from highly n-doped Si through multiple valleys of 1L-MoS2 provides a tremendous opportunity in gate-induced manipulation in Spin-Valley Qubit technology operational at deep cryogenic temperatures (mK).