Substrate-dependent fractal growth and wettability of N+ ion implanted V2O5 thin films

Abstract

Wettability of active material surface affects the electrolyte and electrode-material interaction in electrochemical applications. An increase in the V2O5 electrode's wetting behaviour allows for better contact with the electrolyte. The surface properties of the V2O5 sample were examined in order to evaluate its wettability. In this work, the surface growth of V2O5 thin films on three different substrates (glass, silicon, and sapphire) after 16 keV N+ ion implantation is presented as a function of ion dose. Thin films of 500 nm V2O5 deposited on different substrates show the formation of the nanocrystalline structure over the surface after thermal annealing. Silicon substrate shows the formation of V2O5 nanorods over the surface. Surface morphology shows the growth dynamics of the surface in terms of roughness (α) and growth (β) exponents. Lateral growth of surface features has been quantified in terms of co-relation length (ξ) and fractal dimensions (Df). The scaling laws studies of the surfaces in terms of exponents and co-relation length shows the role of N+ implantation in structural modifications. Furthermore, wetting dynamics have been co-related with fractal growth of the films under ion implantation. The contact angle of V2O5 thin films is found to be higher for V2O5 nanorods on silicon substrate as compared to crystallite grains on sapphire. The present study showed that the surface morphology and wettability of V2O5 are mainly substrate-dependent and can be controlled by surface fractal parameters.