Synthesis and gas sensitivity of thin chromium oxide films

Thin polycrystalline Cr$_{2}$O$_{3}$ films were obtained using RF magnetron sputtering followed by annealing in air at $T$ = 673 K. The obtained films had grain diameters within 40–70 nm and a bandgap width of 3.3 $\pm$ 0.2 eV. In a temperature range of 303–473 K, sensors based on these Cr$_{2}$O$_{3}$ films exhibited high response to NO$_2$, H$_2$, acetone and toluene vapors, while weakly responding to the presence of CH$_4$ and CO and showing relatively weak dependence of the electric resistance on air humidity. A qualitative model of the influence of gases on the electrical properties of thin Cr$_{2}$O$_{3}$ films is proposed.