Environment-insensitive and gate-controllable photocurrent enabled by bandgap engineering of MoS₂ junctions

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) materials possess unique properties due to their high surface-to-volume ratio.
• Environmental factors significantly influence the electronic properties of 2D materials.
• Current methods to stabilize 2D materials, like encapsulation, involve complex fabrication.

Purpose of the Study:

• To investigate environmental effects on photocurrent in molybdenum disulfide (MoS2) junctions.
• To explore methods for controlling transport properties without encapsulation.
• To demonstrate a new design strategy for 2D material-based optoelectronics.

Main Methods:

• Fabrication of MoS2 junctions.
• Measurement of short-circuit photocurrent under varying environmental conditions (vacuum to ambient).
• Analysis of photocurrent dependence on bias and environmental factors.

Main Results:

• Short-circuit photocurrent in MoS2 junctions shows remarkable insensitivity to environmental changes.
• This insensitivity is attributed to diffusion current, dependent on carrier density gradients.
• Photocurrent under bias exhibits persistent photoconductivity and is highly environment-dependent.

Conclusions:

• The environment-insensitive short-circuit photocurrent offers a pathway for stable 2D material devices.
• This characteristic provides an alternative to encapsulation for environmental control.
• Enables robust optoelectronic applications using 2D materials like MoS2.