Non-Destructive Low-Temperature Contacts to MoS2 Nanoribbon and Nanotube Quantum Dots

TL;DR

This paper demonstrates that inserting a bismuth semimetal layer as a contact to MoS2 nanoribbons and nanotubes significantly improves contact quality, enabling stable quantum transport and Coulomb blockade at cryogenic temperatures.

Contribution

It introduces a novel low-temperature contact method using bismuth to enhance quantum device performance in MoS2 nanostructures.

Findings

Two-point resistance around 100kΩ at room temperature

Clear Coulomb blockade observed at cryogenic temperatures

Absence of trap states and reduced disorder at contacts

Abstract

Molybdenum disulfide nanoribbons and nanotubes are quasi-1D semiconductors with strong spin-orbit interaction, a nanomaterial highly promising for quantum electronic applications. Here, it is demonstrated that a bismuth semimetal layer between the contact metal and this nanomaterial strongly improves the properties of the contacts. Two-point resistances on the order of 100k$\Omega$ are observed at room temperature. At cryogenic temperature, Coulomb blockade is visible. The resulting stability diagrams indicate a marked absence of trap states at the contacts and the corresponding disorder, compared to previous devices that use low-work-function metals as contacts. Single-level quantum transport is observed at temperatures below 100mK.