Evaluation of In2O3 prepared by the delayed ignition combustion process as a gas sensor

Metal oxide semiconductor (MOS) gas sensors based on thin film technology offer the potential of higher sensitivity and faster response and recovery than their thick film counterparts. Solution-based approaches are facile and inexpensive routes to prepare thin films. They also provide the means to control and tune the final MOS morphology. Here we present an analysis of 35nm thick indium oxide-based MOS films prepared using two methodologies: a traditional sol-gel process, used as a benchmark, and Delayed Ignition of Combustion (DICO), a more recent process that we are evaluating for gas sensing. The latter process offers a route to the thin film oxides at lower cure temperatures, using ionic oxidizers and organic ignition fuels. We analyze and compare the morphological and compositional properties of the films by means of SEM, TEM, RBS and x-ray techniques. For films of comparable thickness, we evaluate the response to acetone down to the sub-ppm level and establish structure-property relationships.