Electronic Spectroscopy of Atomic Defects in Molybdenum Disulfide under Ambient Conditions

TL;DR

This study uses conductive atomic force microscopy to analyze the electronic properties of individual defects in MoS2 under ambient conditions, revealing defect types and their local conductance effects.

Contribution

It provides a detailed spectroscopic characterization of atomic defects in MoS2, identifying their chemical nature and electronic behavior under realistic conditions.

Findings

Defects categorized into distinct groups based on spectroscopy data.

Identified defects include n-type and p-type transition metal substitutions and oxygen substitutions.

Local conductivity varies with defect type and bias voltage.

Abstract

Transition metal dichalcogenides (TMDs) attract significant attention as potential building blocks in next-generation electronic devices. On the other hand, a comprehensive understanding of how various defects affect local electronic properties under realistic operational conditions is yet to be formed. Here, we present results of electronic spectroscopy experiments performed on individual defects in the prototypical TMD molybdenum disulfide (MoS2) under ambient conditions, by way of conductive atomic force microscopy (C-AFM). Data acquired in the form of consecutive, high-resolution current maps at various bias voltages allow the assessment of local conductivity and differential conductance as a function of bias voltage for individual defects, the effects of which range from single atomic sites to several nanometers in lateral size. Characteristic behavior in spectroscopy data allows the categorization of observed defects into distinct groups, and their chemical identification as n-type and p-type transition metal substitutions of molybdenum atoms, as well as oxygen substitutions of sulfur atoms.