Lateral monolayer MoS₂ homojunction devices prepared by nitrogen plasma doping

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Monolayer molybdenum disulfide (MoS₂) exhibits excellent electron mobility, flexibility, and a direct band gap, making it suitable for advanced electronic and optoelectronic applications.
• Flexible and wearable devices require novel semiconductor materials with tunable electronic properties.

Purpose of the Study:

• To fabricate lateral monolayer MoS₂ homojunctions (pn and npn) using a selective nitrogen plasma doping technique.
• To investigate the electronic and photoelectric properties of these MoS₂-based homojunctions for potential device applications.

Main Methods:

• Synthesis of monolayer MoS₂ thin films via chemical vapor deposition.
• Characterization using photoluminescence, atomic force microscopy, and Raman spectroscopy.
• Fabrication of lateral pn and npn homojunctions through nitrogen plasma selective doping.

Main Results:

• The pn homojunction diode demonstrated a high rectifying ratio of approximately 10³.
• As a photodetector, the pn homojunction achieved optical responsivity up to 48.5 A W^-1, external quantum efficiency of 11,301%, detectivity of ~10⁹ Jones, and a response time of 20 ms.
• The npn homojunction functioned as a bipolar junction transistor with an amplification coefficient reaching ~10².

Conclusions:

• A controllable plasma doping technique, compatible with CMOS processes, was successfully employed to create MoS₂-based homojunctions.
• These results highlight the potential of 2D materials like MoS₂ for next-generation flexible electronic and optoelectronic devices and circuits.