Role of Defect Induced Interfacial States in Molecular Sensing: Ultrahigh- Sensitive Region for Molecular Interaction

TL;DR

This paper demonstrates a highly sensitive molecular sensing method using defect-induced interfacial states in a 2D molybdenum disulfide transistor, achieving nearly three orders of magnitude sensitivity at room temperature.

Contribution

It introduces a nondestructive technique to generate charge states via defect engineering in 2D materials, enhancing molecular detection sensitivity.

Findings

Conductance fluctuation correlates with molecular concentration up to parts-per-billion.

Interfacial states modulate conductance in response to gas molecules.

First-principles calculations explain the role of interfacial configurations.

Abstract

The defect induced interfacial states are created in an atomically thin two-dimensional molybdenum disulfide channel by underlying a narrow pattern of a graphene layer in a field effect transistor. Nondestructive method for the generation of charge-state allowed a highly sensitive molecular interaction with the sensitivity of nearly three-order of magnitude at room temperature. The presence of interfacial states in the channel lead to a conductance fluctuation and its magnitude is modulated using the nitrogen dioxide gas molecules in the subthreshold region. The study provides a systematic approach to establish a correlation between modulated conductance fluctuation and the molecular concentration upto parts-per-billion. First-principles density functional theory further explains the role of unique interfacial configuration on conductance fluctuation. Therefore, our study demonstrates an experimental approach to induce charge-state for the modulation of carrier concentration and exploits the role of defect induced interfacial states in atomically thin interfaces for the molecular interaction.