Anisotropic sensing based on single ReS₂flake for VOCs discrimination

Area of Science:

• Materials Science
• Chemical Sensing
• Nanotechnology

Background:

• Selective detection of volatile organic compounds (VOCs) is crucial for environmental monitoring and medical diagnostics.
• Two-dimensional (2D) materials offer unique electronic properties for advanced sensor applications.
• In-plane anisotropy in 2D materials can be exploited for enhanced sensing capabilities.

Purpose of the Study:

• To develop a highly selective and sensitive VOC sensor using an anisotropic rhenium disulfide (ReS2) field-effect transistor (FET).
• To investigate the effect of ultraviolet (UV) illumination on the sensing performance of ReS2 FETs.
• To demonstrate the capability of a single ReS2 FET to distinguish between different VOCs.

Main Methods:

• Fabrication of a ReS2 FET utilizing its distinct in-plane anisotropy.
• Exposure of the ReS2 FET to four different VOCs (acetone, methanol, ethanol, IPA) under both dark and UV illumination conditions.
• Analysis of sensor responses along the *a*-axis and *b*-axis of ReS2.
• Application of principal component analysis (PCA) to differentiate VOCs based on sensor responses.

Main Results:

• ReS2 FET exhibited different responses along the *a*-axis and *b*-axis to various VOCs.
• UV illumination significantly enhanced the ReS2 response, amplifying it 10-15 times for acetone.
• The detection limit for acetone decreased from 70 ppm to 4 ppm under UV light.
• PCA successfully separated the data points for acetone, ethanol, methanol, and IPA, demonstrating high gas species discrimination ability.

Conclusions:

• A single ReS2 FET with in-plane anisotropy can achieve selective and sensitive VOC detection.
• UV illumination is an effective strategy to enhance the performance of anisotropic 2D material-based gas sensors.
• This approach holds promise for developing advanced sensing platforms for practical VOC recognition applications.