Strain engineering of optical properties in VO₂ thin films on muscovite

Hsiao-Wen Chen^1*, Chien-I Li², Chun-Hao Ma², Ying-Hao Chu², Hsiang-Lin Liu¹

¹Department of Physics, National Taiwan Normal University, Taipei, Taiwan
²Department of Materials Science Engineering, National Chiao Tung University, Hsinchu, Taiwan

* Presenter:Hsiao-Wen Chen, email:josephmdtw@gmail.com

We investigated the influence of uniaxial mechanical stain on the optical properties of VO₂ thin films through Raman scattering and optical transmittance measurements. The films were grown on flexible muscovite substrates through pulsed laser deposition. Under applied strain, the linear shifts in peak positions of Raman-active phonon modes at approximately 340, 309, and 391 cm^-1 were observed. The extracted Grüneisen parameter values were approximately between 0.44 and 0.57. Furthermore, a pronounced strain-induced change in metal-insulator transition (MIT) temperature was observed, decreasing for compressive strain, and increasing for tensile strain. The rates of MIT temperature variation reached 4.5 °C /% and 7.1 °C /% at a wavelength of 1200 nm during the heating and cooling processes, respectively. These results demonstrate that modulation of the optical properties of VO₂ thin films on muscovite is controllable and reversible through strain engineering, opening up new opportunities for application in flexible and tunable photonic devices.

Keywords: vanadium dioxide, Raman spectroscopy, strain, optical transmittance spectra