Lateral multilayer/monolayer MoS₂ heterojunction for high performance photodetector applications

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) materials exhibit unique thickness-dependent electronic properties.
• Heterojunctions formed from these materials offer potential for advanced electronic and optoelectronic devices.
• Molybdenum disulfide (MoS2) is a prominent 2D material with tunable band structure.

Purpose of the Study:

• To investigate the electronic and optical properties of a lateral multilayer/monolayer MoS2 heterojunction.
• To assess the performance of this heterojunction as a photodetector.
• To understand the role of the heterojunction in photocurrent generation.

Main Methods:

• Fabrication of a photodetector using as-exfoliated lateral multilayer/monolayer MoS2.
• Characterization of current-rectifying properties via gate-tunable measurements.
• Evaluation of photodetective performance under ultraviolet to visible light illumination.

Main Results:

• Observed good gate-tunable current-rectifying characteristics with a ratio of 10^3 at 10 V.
• Demonstrated outstanding photodetective performance: photoresponsivity of 10^3 A/W, photosensitivity of 1.7 × 10^5, and detectivity of 7 × 10^10 Jones at 470 nm.
• Identified an abnormal photoresponse under positive gate voltage, highlighting the heterojunction's role in photocurrent generation.

Conclusions:

• The study provides evidence for the existence and functionality of the multilayer/monolayer MoS2 heterojunction.
• Results contribute to a fundamental understanding of band alignment in MoS2 heterojunctions.
• The findings suggest a feasible pathway for developing novel electronic and optoelectronic devices based on MoS2 heterojunctions.