Study of gold and bismuth electrical contacts to a MoS$_{2}$ monolayer

TL;DR

This paper explores different contact materials and techniques for MoS$_{2}$ monolayers, comparing gold and bismuth contacts, and introduces AFM ironing to improve contact quality, with preliminary optical response results.

Contribution

It presents a comparative study of gold and bismuth contacts on MoS$_{2}$, including a novel AFM ironing method to enhance contact performance.

Findings

Bi contacts show different I-V characteristics compared to gold.

AFM ironing improves gold contact parameters.

Preliminary optical responses vary between contact types.

Abstract

Semiconducting transition metal dichalcogenides (TMDCs) present new possibilities for designing novel electronic devices. An efficient contacting scheme is required to take advantage of exceptional opto-electronic properties of TMDCs in future electronic devices. This is however challenging for TMDCs, mostly due to the typically high Schottky barrier formed between a metal and a semiconductor. Here we investigate different approaches for contacting MoS$_{2}$, utilizing both metallic gold and semimetallic bismuth as contact materials. The collected I-V characteristics of Bi-contacted devices are compared with the performance of traditional gold contacts. The method of AFM ironing, which we used to enhance the parameters of gold contacts, is also described. Additionally, we show preliminary results regarding an optical response for both types of samples.