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

Abstract

In the data analytics era, the development of superior metal oxide semiconductor (MOS) gas sensors is of paramount importance. In this paper, we report an analysis of 35nm thick indium oxide films prepared using two simple, solution-based methodologies: a traditional sol-gel process (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 MOS thin films at lower cure temperatures, using ionic oxidizers and organic ignition fuels. We find that the radically different chemical reactions between sol-gel chemistry and DICO lead to the formation of In2O3 with very different morphologies, and consequently with significantly different gas sensivity. The significantly smaller grain size yielded by DICO is critical to enhance In2O3 gas sensitivity. The latter result, in conjunction with the versatility and low temperature associated with the DICO process clearly show the high potential of the latter for gas sensing applications.