A Raman study of NiO/sub x/ films for gas sensors applications

Abstract

NiO/sub x/ films were prepared by dc reactive magnetron sputtering in an Ar+O/sub 2/ mixed atmosphere. These films were investigated by Raman spectroscopy and SIMS. It was confirmed that as we increased the ratio of oxygen in the oxygen/ argon mixture to 30-40%, the composition of the layers approached the Ni/sub 2/O/sub 3/ composition. Annealing of the layers also led to a change in composition from the nearly perfect (NiO) to a stoichiometry with an excess of O/sub 2/(/spl sim/Ni/sub 2/O/sub 3/).