Dielectric-Free MoS₂/VO₂ Junction Field-Effect Transistor with Sensitive and Ultrafast Photoresponse for Light...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• The Internet of Things and mobile devices necessitate advanced on-chip photodetection.
• Two-dimensional (2D) materials offer excellent optoelectronic properties for photodetectors.
• Achieving high responsivity, low noise, and fast response in 2D phototransistors remains a challenge.

Purpose of the Study:

• To develop a hybrid MoS2/VO2 junction field-effect transistor (JFET) to address the sensitivity-speed tradeoff in 2D photodetectors.
• To leverage the van der Waals (vdW) interface and VO2 gate for enhanced device performance.
• To enable self-powered photodetection and explore applications in low-power light encoding.

Main Methods:

• Fabrication of a hybrid MoS2/VO2 junction field-effect transistor (JFET).
• Utilizing the van der Waals (vdW) interface and VO2 gate to control the depletion region.
• Characterization of device performance including subthreshold swing, gate hysteresis, responsivity, detectivity, and response times.

Main Results:

• The JFET achieved a minimal subthreshold swing (80 mVdec-1) and low gate hysteresis (10 mV).
• High responsivity (10^3 AW-1) and specific detectivity (10^12 Jones) were observed.
• Fast response times (rise/decay: 8/10 µs) and self-powered photodetection at elevated temperatures were demonstrated.

Conclusions:

• The hybrid MoS2/VO2 JFET effectively balances sensitivity and speed for 2D photodetectors.
• The device's performance is attributed to the asymmetric vdW heterojunction and enhanced built-in electric field.
• The JFET is suitable for low-power light encoding in encrypted communication, paving the way for integrated 2D optoelectronics.