VO2 materials and devices

Micro & Nano Characterization Group

MNC Group

VO2 is a material that undergoes an insulator to metal transition at 68°C. This transition is followed by a strong change in its electrical resistivity and by its optical properties.

We fabricate by sol-gel methods thin films of VO2 on various substrates (Si, SiO2, Sapphire). Our aim is :

- study and understand the mechanisms of the transition at the sub micron scale (high resolution optical imaging, AFM measurements, electrical measurements)

- develop neuromorphic devices

- use the strong variations of the optical properties to design optical modulators

Fig. 1: surface of VO2 observed by optical microscopy at high mignification. The red and blue zones are VO2 grains that have slight variations of the transition temperature.

See for instance:

- Phys. Rev. Lett. 110, 056601 (2013).

- Phys Rev B 107, 205121 (2023).

- Adv. Electron. Mater 9(10), 2300085 (2023).

Fig. 2: Near-field above an array of gold nanodisks: experiment (top) and simulation (bottom). The arrows indicate the incident polarization direction.