Modulating strain by growth interrupted deposition of polycrystalline V₂O₃ films on SiO₂/Si substrates with improved metal–insulator transition characteristics

We present a novel method for controlling the strain in polycrystalline V₂O₃ films through the utilization of growth interrupted deposition. Our results demonstrate a simple approach to tune and improve the metal–insulator transition (MIT) characteristic of V₂O₃ films of a given thickness by controlling the number of growth interruptions (i.e. the thickness of individual layers for a fixed total film thickness). Determining the strain in the films from x-ray diffraction scans reveals a relaxation of the out-of-plane compressive strain with increasing number of interruptions. Atomic force microscopy shows the films to follow a Volmer–Weber growth mode of 3D-nanostructures, the density and size of which varies with increasing V₂O₃ thickness and number of growth interruptions. Superior metal–insulator transition characteristics are observed for interruptions resulting in a 5 nm interruption layer thickness. Such films show a ∼2 order of magnitude larger resistance change and a reduction in the transition temperature of ∼40 K along with a narrowing of the MIT-hysteresis compared to that of continuously grown films.