Tunable GaTe-MoS2 van der Waals p-n Junctions with Novel Optoelectronic Performance

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Vertically stacked van der Waals (vdW) materials offer potential for advanced electronics and optoelectronics.
• Realizing p-n vdW junctions is challenging due to the scarcity of intrinsic p-type vdW materials, often requiring electrical gating, specialized electrodes, or chemical doping.
• Gallium telluride (GaTe) is an intrinsic p-type vdW material with a high charge density and a thickness-independent direct band gap.

Purpose of the Study:

• To construct and characterize an ultrathin, tunable p-GaTe/n-MoS2 vdW heterostructure.
• To investigate the photovoltaic and photodetecting properties of the fabricated heterostructure.
• To demonstrate the potential of this heterostructure for next-generation electronic and optoelectronic devices.

Main Methods:

• Fabrication of vertically stacked p-GaTe/n-MoS2 heterostructures.
• Characterization of the vdW heterostructure's electronic and optoelectronic properties.
• Performance evaluation including rectification ratio, external quantum efficiency, photoresponsivity, and detectivity.

Main Results:

• Achieved high rectification ratio (4 × 10^5), external quantum efficiency (61.68%), and photoresponsivity (21.83 AW⁻¹).
• Demonstrated a detectivity of up to 8.4 × 10^13 Jones, exceeding that of commercial silicon and InGaAs photodetectors.
• Confirmed the ultrathin and tunable nature of the p-GaTe/n-MoS2 vdW heterostructure.

Conclusions:

• The p-GaTe/n-MoS2 vdW heterostructure exhibits superior photovoltaic and photodetecting performance.
• This material system presents a promising alternative for high-performance optoelectronic applications.
• The study highlights the potential of intrinsic p-type vdW materials like GaTe in device fabrication.