BITAVOX coatings obtained by reactive magnetron sputtering: Influence of thickness and composition

BITAVOX (Bi2TaxV1 − xO5.5) thin films with different thicknesses or compositions were deposited from Bi, Ta and V targets by reactive magnetron co-sputtering. As-deposited films are amorphous and have to be thermally treated at 700 °C for 2 h in order to crystallise. Increasing thickness leads to enhanced compressive stress. Moreover, porosity appears in the as-treated films. The electrochemical characterisation showed that the film resistance decreased with increasing thickness. Furthermore, the activation energies of the films are rather high in comparison with the bulk material, which can be attributed to a strong contribution of the inter-grain conduction to the total conductivity.