Vertical MoSe₂-MoO _x p-n heterojunction and its application in optoelectronics

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Van der Waals (vdW) heterojunctions are crucial for next-generation electronic and optoelectronic devices.
• Developing stable and efficient n-type 2D transition-metal dichalcogenide (TMD)/p-type oxide interfaces remains a challenge.

Purpose of the Study:

• To synthesize and characterize novel hybrid n-type 2D TMD/p-type oxide vdW heterojunction nanosheets.
• To investigate the current-rectifying properties and gate voltage tunability of vertical MoSe₂-MoO_x p-n heterojunctions.
• To evaluate the performance of photodetectors based on these heterojunctions.

Main Methods:

• Chemical vapor deposition (CVD) technique used to grow MoSe₂-MoO_x heterojunction nanosheets on SiO₂/Si substrates.
• Characterization of structural properties, including regular hexagon structures with dimensions up to ~8 μm.
• Fabrication and testing of vertical p-n heterojunctions for electrical and photoresponse measurements.

Main Results:

• Successfully synthesized hybrid n-type MoSe₂/p-type MoO_x vdW heterojunction nanosheets for the first time.
• Demonstrated significant current-rectifying characteristics in vertical MoSe₂-MoO_x p-n heterojunctions, tunable via gate voltage.
• Achieved high responsivity (3.4 A W^-1), detectivity (0.85 × 10⁸ Jones), and external quantum efficiency (1665.6%) in a photodetector at 254 nm.

Conclusions:

• The developed MoSe₂-MoO_x heterojunctions offer a promising platform for high-performance optoelectronic devices.
• These findings provide a foundational building block for exploring flexible and transparent vdW electronics.
• Further optimization of device structures can lead to enhanced electronic and optoelectronic performance.