Strain-Induced Modulation of Resistive Switching Temperature in Epitaxial VO₂ Thin Films on Flexible Synthetic Mica

Abstract

The resistive switching temperature associated with the metal−insulator transition (MIT) of epitaxial VO 2 thin films grown on flexible synthetic mica was modulated by bending stress. The resistive switching temperature of polycrystalline VO 2 and V 2 O 5 thin films, initially grown on synthetic mica without a buffer layer, was observed not to shift with bending stress. By inserting a SnO 2 buffer layer, epitaxial growth of the VO 2 (010) thin film was achieved, and the MIT temperature was found to vary with the bending stress. Thus, it was revealed that the bending response of the VO 2 thin film depends on the presence or absence of the SnO 2 buffer layer. The bending stress applied a maximum in-plane tensile strain of 0.077%, resulting in a high-temperature shift of 2.3 °C during heating and 1.8 °C during cooling. After 10 4 bending cycles at a radius of curvature R = 10 mm, it was demonstrated that the epitaxial VO 2 thin film exhibits resistive switching temperature associated with MIT.

Mechanical Bending Strain-Actuated Modulation of Metal–Insulator Transition Temperature in Flexible Epitaxial V2O3 Films

“…The design and fabrication of flexible oxide films have recently attracted considerable interests. − Among various integration strategies utilized, the direct deposition of oxide films on a flexible inert mica substrate has caught much attention due to its benefits in thermal stability, resilience against extreme environments, low-cost manufacturing, and easy large-scale integration. , Hence, ever-increasing examples showcasing integration of oxide materials on mica have been reported, demonstrating superior performance and excellent flexibility in the oxide/mica heterostructures. − The oxide growth on mica is regarded as a form of quasi-van der Waals epitaxy (Q-vdWE) growth, wherein both van der Waals and chemical interactions bond the film layer to the substrate . Especially fascinating is the bending strain-actuated modulation of the physical properties in the flexible oxide/mica heterostructures, such as SrRuO 3 /BaTiO 3 /mica, Pr 0.5 Ca 0.5 MnO 3 /mica, and NdNiO 3 /mica, etc., showing great application potential in the fields of stretchable integrated circuits, portable electronic devices, sensor networks, and human-machine interaction devices. − …”

Tuning the Intrinsic Stochasticity of Resistive Switching in VO2 Microresistors

“…Second, the possible higher proportion of rutile VO 2 within the small-grain film insulating state, and the possible presence of another vanadium oxide phase (hinted by XRD measurements), could impact filament formation. Third, residual stresses and strain (known to have large impacts on the IMT , ) could be present with larger inhomogeneity in the large-grain film. In addition to these differences, dynamic effects related to the decay of persistent metallic islands could play a role.…”