Nanowires of different metal oxides (SnO2, ZnO) have been grown by evaporation–condensation process. Their chemical composition has been investigated by using XPS. The standard XPS quantification through main photoelectron peaks, modified Auger parameter and valence band spectra were examined for the accurate determination of oxidation state of metals in the nanowires.Morphological investigation has been conducted by acquiring and analyzing the SEM images. For the simulation of working conditions of sensor, the samples were annealed in ultra high vacuum (UHV) up to 500 °C and XPS analysis repeated after this treatment. Finally, the nanowires of SnO2 have were used to produce a novel gas sensor based on Pt/oxide/SiC structure and operating as Schottky diode. Copyright © 2008 John Wiley & Sons, Ltd.