Indium oxide-based gas sensors have been proven to be a promising material for detecting nitrogen dioxide (NO2) gas because of its wide bandgap and stability. In this paper, the enhancement mechanism for the sensitivity of indium oxide NO2 gas sensors was systematically investigated using density functional theory (DFT) calculations and experimental validation with noble metals like Au, Ag, Pt, Pd, and Cu. We have fabricated a GaN nanowire-based NO2 gas sensor functionalized with In2O3 and decorated with noble metals using a standard fabrication technique. Experimental tests showed that Au/In2O3 sensors exhibited the highest response of 38.9% followed by bare In2O3 with 10% for 10 ppm NO2 at room temperature. The sensing properties were mainly attributed to a spillover effect or catalytic performance of Au with In2O3. The adsorption energies, charge transfers, and band gap confirm the enhanced sensing capability of Au-decorated Indium oxide for a NO2 gas sensor.
Raju et al. (2025) studied this question.