Intrinsic anomalous scaling of epitaxial vanadium dioxide thin films on titanium dioxide

Abstract

We present dynamic scaling studies during growth of epitaxial vanadium dioxide (VO2) thin films deposited on titanium dioxide TiO2(002). The main goal was to evaluate the evolution of the VO2 surfaces using films of different thicknesses to extract a series of growth exponents which determine the surface morphology and microstructure. We applied this evaluation for thin (∼5nm) to thick (∼100nm) films and determined the growth dynamics at thicknesses of interest for VO2 thin film applications. By analyzing the evolution of surface roughness, power spectral density, and correlation functions over the film thicknesses, we obtained the growth exponents that allowed us to characterize these films as belonging to the intrinsic anomalous scaling class. Such growth behavior suggests that nonlocal effects play a significant role during film growth, as these nonlocal effects arise from the growth method, strain dynamics at the film/substrate epitaxial heterojunction and the resulting grain structure of our films.