Intense conductivity suppression by edge defects in zigzag MoS2 and WSe2 nanoribbons: a density functional based...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Understanding electron transport in low-dimensional materials is crucial for nanoelectronics.
• Molybdenum disulfide (MoS2) and tungsten diselenide (WSe2) nanoribbons are promising for future electronic devices.
• Edge defects can significantly alter material properties.

Purpose of the Study:

• To investigate the impact of edge vacancies on the electron transport properties of zigzag MoS2/WSe2 nanoribbons.
• To quantify the conductance changes induced by single and multiple edge defects.
• To explore the relationship between defect geometry and transport behavior.

Main Methods:

• Density Functional Theory (DFT) based tight-binding model with sp(3)d(5) basis set for electronic structure.
• Landauer-Büttiker approach for calculating electronic transport.
• SIESTA DFT calculations to corroborate findings on electronic band localization.

Main Results:

• A single edge vacancy (missing MoS2/WSe2 triplet) reduces conductance by approximately 50% near the Fermi level.
• Subsequent defects on the same edge have minimal additional impact, indicating strong initial suppression.
• Defects on opposite edges further reduce quantum conductance, irrespective of their relative positions.
• Additional defects lead to energy-dependent conductance suppression and geometry-dependent peaks.

Conclusions:

• Edge vacancies critically influence electron transport in MoS2/WSe2 nanoribbons.
• The placement and number of defects significantly alter conductance.
• These findings highlight the sensitivity of nanoribbon transport to structural imperfections, crucial for device design.