Enhanced Photobolometric Effect in an All-Semimetal van der Waals Heterostructure

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Van der Waals (vdWs) semimetallic materials offer potential for ultrabroadband photodetection.
• Individual 2D semimetals suffer from high dark current and low temperature coefficient of conductance (TCC), limiting device performance.

Purpose of the Study:

• To enhance the photobolometric effect in 2D semimetals for improved photodetection.
• To overcome limitations of individual 2D semimetals by creating heterostructures.

Main Methods:

• Fabrication of a heterostructure using 2D semimetallic transition metal dichalcogenides (TMDs), specifically TiS2 and WTe2.
• Utilized standard transport and photocurrent measurements to characterize the heterostructure.
• Investigated the effect of photosensitive channel length on device performance.

Main Results:

• The TiS2-WTe2 heterostructure exhibits an enhanced photobolometric effect in the junction area at low temperatures.
• Photocurrent shows varying temperature dependencies across different device regions.
• Photoresponse remains detectable up to room temperature with a good signal-to-noise ratio.

Conclusions:

• The TiS2-WTe2 heterostructure design improves photodetector performance by enhancing the photobolometric effect.
• Device performance can be tuned by adjusting the photosensitive channel length.
• Findings provide insights for designing advanced thin-film optoelectronic devices with improved functionality.