Force and light tuning vertical tunneling current in the atomic layered MoS₂

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Bilayer molybdenum disulfide (MoS2) is a promising two-dimensional material for electronic applications.
• Understanding electrical transport in MoS2 under external stimuli is crucial for device development.

Purpose of the Study:

• To investigate the vertical electrical transport behavior of bilayer MoS2 under coupled force and light.
• To analyze the tunneling mechanisms and their dependence on applied force and illumination.
• To explore the potential for force and light to tune the electronic properties of MoS2 junctions.

Main Methods:

• Utilizing conductive atomic force microscopy (c-AFM) to probe vertical transport.
• Analyzing current-voltage (I-V) characteristics using Simmons approximation for tunneling.
• Investigating the effects of applied force and light on the tunneling barrier.

Main Results:

• The current-voltage behavior follows Simmons approximation, exhibiting direct tunneling at low bias and Fowler-Nordheim tunneling at high bias.
• Transition voltage and tunnel barrier height were extracted and found to be tunable.
• Source-drain current unexpectedly decreases with increasing force, with the dropping point modulated by light, indicating force and light-induced tuning of barrier height and width.

Conclusions:

• Force and light effectively tune the tunneling barrier height and width in bilayer MoS2 junctions.
• This work presents a novel approach for designing electronic and optoelectronic devices using ultrathin 2D materials.
• The findings are significant for developing high-efficiency electronic components with ultrashort channel lengths based on tunneling currents.