Negative photoresponse in Ti₃C₂T MXene monolayers

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional transition metal carbides, nitrides, and carbonitrides (MXenes) are emerging materials with diverse applications.
• MXenes show promise in optoelectronics and photonics, but their intrinsic photoresponse is not well understood.

Purpose of the Study:

• To investigate the visible and near-infrared photoresponse of the prominent MXene material, Ti3C2Tx.
• To characterize the electrical properties of individual monolayer Ti3C2Tx flakes under illumination.

Main Methods:

• Fabrication of devices using individual monolayer Ti3C2Tx flakes.
• Electrical measurements under white light and laser illumination (visible and near-infrared).
• Characterization using various microscopic and spectroscopic techniques.

Main Results:

• A reproducible decrease in current was observed upon illumination, indicating a negative photoresponse.
• The negative photoresponse was consistent across different electrode configurations and wavelengths.
• Electrical measurements confirmed the photoresponse of Ti3C2Tx MXene.

Conclusions:

• The study demonstrates the intrinsic negative photoresponse of Ti3C2Tx MXene in the visible and near-infrared range.
• Understanding this photoresponse is crucial for advancing optoelectronic and photonic applications of MXenes.
• This research provides foundational knowledge for designing MXene-based photodetectors and other photonic devices.