Thickness-dependent microstructure and metal-insulator transition in vanadium dioxide thin films grown by pulsed laser deposition

Abstract Vanadium dioxide (VO 2 ) thin films with thicknesses of 30, 60, 100, and 230 nm were grown on c -plane sapphire substrates using pulsed laser deposition. To explore the relationship between film thickness and metal-insulator transition behavior, we investigated the microstructural and electrical properties of the VO 2 films. X-ray diffraction (XRD), electron spectroscopy for chemical analysis, scanning electron microscopy, transmission electron microscopy (TEM), and electrical resistance measurements were performed to analyze the fabricated films. XRD patterns confirmed the phase composition of the VO 2 films, while TEM images revealed the epitaxial relationship between the VO 2 films and the c -plane sapphire substrates. Notably, both grain size and transition magnitude near 68 °C in the resistivity–temperature ( ρ –T) curve increased with film thickness, highlighting the critical role of film thickness in the electrical characteristics of two-terminal VO 2 -based devices.