Voltage triggered near-infrared light modulation using VO₂ thin film.

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Compact and fast modulators for infrared light are crucial for applications in communication, imaging, and sensing.
• Vanadium dioxide (VO2) exhibits a metal-insulator transition (MIT) that can be triggered by temperature or electric fields, making it a promising material for optical modulation.

Purpose of the Study:

• To investigate the development of electric-field-induced fast modulators for near-infrared light.
• To explore the use of VO2 thin films on Gallium Nitride (GaN) suspended membranes for optical modulation.

Main Methods:

• Fabrication of VO2 thin films on GaN suspended membranes.
• Utilizing an interdigitated finger geometry to apply electric fields.
• Measuring the reduction in transmitted light intensity at near-infrared wavelengths (790 and 1550 nm).
• Performing finite element simulations to understand the modulation mechanism.

Main Results:

• Observed a 7% and 14% reduction in transmitted light intensity at 790 nm and 1550 nm, respectively, due to the metal-insulator transition in VO2.
• Demonstrated near-infrared light modulation with voltage pulse widths as low as 300 µs at 25 V.
• Finite element simulations indicated that Joule heating and electric field synergistically induce the phase transition.

Conclusions:

• Successfully demonstrated a fast, electrically controlled optical modulator based on VO2 thin films on suspended GaN membranes.
• The developed modulator shows significant potential for high-speed optical modulation in near-infrared applications.
• The findings highlight the viability of using phase-change materials like VO2 for advanced optoelectronic devices.