Interplay of deposition kinetics with metal diffusion in MoO3-Cu heterojunctions

Abstract

Metal oxide-metal heterojunctions are tunable structural and electronic systems characterised by defect density and diffusion properties. The junction formation’s kinetics and adatoms surface energy affect both nucleation and diffusion processes. The mechanism and the dependence of structural and electronic properties on these parameters are still not truly understood. Structural and electronic configuration dynamics of MoO${}_3$ thin films deposited on metallic Cu and Si wafer are investigated by changing the kinetics of the deposition. Films obtained by Pulsed Laser Deposition and Thermal Evaporation techniques having different kinetic energy ranges are compared. It is shown that the diffusion competition between oxide and metallic elements on the amorphous layer plays a critical role in the formation of vacancies and the ionic redistribution within the junction. It is also shown that the metallic diffusion can be tuned via the interchange between the incident adatoms’ initial kinetic energy and the diffusion time during the post-deposition thermal life cycle. These results help to understand the mechanism of the ionic redistribution and dynamics at the oxide/metal junction, providing a tool for tuning structural and electronic properties.