Nanostructured Refractory Metal Oxide Films Produced by a Pulsed Microplasma Cluster Source as Active Layers in Microfabricated Gas Sensors

Cluster-assembled nanostructured films of refractory metal oxides were produced by supersonic cluster beam deposition (SCBD) using a pulsed microplasma cluster source (PMCS). The growth of nanostructured films takes place at room temperature on substrates exposed to nanoparticles beam. Soft landing and limited diffusion are peculiar characteristics of the deposition process, causing the film to grow according to a highly porous structure. We produced nanostructured Mo, W, and Nb oxide films and we characterized their crystal structure and film morphology at the nanoscale together with their gas sensing performances. The effect of thermal treatments on grain growth and morphology modification was particularly addressed in view of the use of the nanostructured layers in gas sensing applications on microfabricated platforms.