Photoconductivity Enhancement in Atomically Thin Molybdenum Disulfide through Local Doping from Confined Water

Area of Science:

• Materials Science
• Nanotechnology
• Condensed Matter Physics

Background:

• Two-dimensional transition metal dichalcogenide (TMDC) materials are promising for opto-electronic devices.
• Material properties of few-layer and single-layer TMDCs are significantly affected by interfaces.
• Understanding nanoscale interfacial effects is crucial for optimizing TMDC device performance.

Purpose of the Study:

• To investigate the influence of confined water on the photoconductivity of bilayer molybdenum disulfide (MoS2) at the nanoscale.
• To explore the relationship between the structural phase of confined water and the electronic properties of the TMDC/substrate interface.
• To determine the impact of interfacial water on photocurrent generation and photopower in MoS2 devices.

Main Methods:

• Utilized photoconductive atomic force microscopy (pc-AFM) to probe local photoconductivity.
• Investigated bilayer molybdenum disulfide (MoS2) grown on a mica substrate.
• Analyzed the effect of water confined at the MoS2/mica interface on electronic properties.

Main Results:

• Observed a local enhancement of photoconductivity at the nanoscale in bilayer MoS2.
• Demonstrated that the structural phase of confined water influences the doping level of MoS2.
• Showed that changes in doping level alter the tunneling barrier, leading to increased photocurrent and photopower generation.

Conclusions:

• Confined water at the TMDC/substrate interface plays a critical role in modulating electronic properties.
• The structural phase of interfacial water directly impacts device performance by altering doping and tunneling barriers.
• This study highlights a novel mechanism for enhancing opto-electronic properties in 2D materials through interfacial engineering.