Niobium oxide nanostructures for chemical sensing

Niobium oxide nanostructures were synthesized by hydrothermal method starting from niobium films deposited by RF magnetron sputtering on 2 × 2 mm2 alumina substrates. The samples were firstly treated with a KOH solution and with HNO3, and then annealed to obtain the Nb2O5 nanostructures. A scanning electron microscope (SEM) was used to investigate the morphology of the samples, while RAMAN spectroscopy was used to analyse their structural properties. In order to study the functional properties of the material, electrical contacts and heating elements were deposited over the substrates by DC magnetron sputtering. The as-prepared samples were mounted on TO packages using gold wires. Afterwards, functional tests were performed in a test chamber to investigate their electrical conductance variation as a function of the surrounding atmosphere and thus the sensitivity to different gaseous species.