Single-Layer ReS₂: Two-Dimensional Semiconductor with Tunable In-Plane Anisotropy

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Rhenium disulfide (ReS2) and rhenium diselenide (ReSe2) are group 7 transition metal dichalcogenides (TMDs) with layered atomic structures.
• These materials exhibit an in-plane motif of parallel diamond-shaped chains (DS-chains).

Purpose of the Study:

• To investigate the correlation between electron transport anisotropy and atomic structure in single-layered ReS2.
• To explore methods for controlling the direction of conducting channels in ReS2 and ReSe2.

Main Methods:

• Transmission electron microscopy (TEM) and transport measurements.
• Density functional theory (DFT) calculations.
• Electron beam irradiation and strain engineering.

Main Results:

• Direct correlation established between electron transport anisotropy in ReS2 and DS-chain orientation.
• Conducting channel direction in ReS2 and ReSe2 is controllable via electron beam irradiation and strain.
• High chalcogen deficiency induces a direction-dependent structural transformation to a nonstoichiometric phase.

Conclusions:

• The in-plane transport behavior of ReS2 and ReSe2 is tunable, offering significant potential for 2D nanoelectronic circuit fabrication.
• Atomic orientation and external stimuli like irradiation and strain are key factors in controlling electronic properties.