Van der Waals MoS₂/VO₂ heterostructure junction with tunable rectifier behavior and efficient photoresponse

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Van der Waals (vdW) heterostructures enable novel electronic devices by combining diverse 2D materials.
• Functional oxides exhibiting insulator-to-metal transitions (IMT) offer unique electrical switching capabilities.
• n-type semiconductor junctions typically require abrupt interfaces for rectification.

Purpose of the Study:

• To fabricate and characterize ultra-thin vdW heterojunctions using molybdenum disulfide (MoS2) and vanadium dioxide (VO2).
• To investigate the electronic and optoelectronic properties of MoS2/VO2 n-n heterojunctions.
• To explore the tunable rectification and photosensitivity of these novel heterojunctions.

Main Methods:

• Deterministic assembly of multilayer MoS2 on VO2 substrates.
• Fabrication of vdW MoS2/VO2 heterojunctions.
• Electronic and optoelectronic characterization, including current-voltage measurements and photoresponse analysis.

Main Results:

• Demonstrated tunable diode-like current rectification with a good ideality factor (1.75) and high conductance swing (120 mV/dec).
• Observed Schottky rectification at higher temperatures (>68°C) or voltages, exploiting VO2's metallic state.
• Showcased unique tunable photosensitivity and excellent junction photoresponse in the 500/650 nm range.

Conclusions:

• The vdW MoS2/VO2 heterojunction effectively combines n-n junction blocking capabilities with tunable conductivity.
• These heterojunctions act as Schottky rectifiers above the insulator-to-metal transition temperature of VO2.
• The demonstrated tunable electronic and optoelectronic properties highlight their potential for next-generation electronic and photonic devices.