Gas-sensitive properties of thin film heterojunction structures based on Fe2O3–In2O3 nanocomposites

This paper reports an investigation of the gas-sensitive properties of thin film sensors based on the double-layers Fe2O3/In2O3 and Fe2O3–In2O3/In2O3 towards gases of different chemical nature (C2H5OH, CH4, CO, NH3, NO2, O3). As it was found, the γ-Fe2O3–In2O3 composite (Fe:In = 9:1, mol) is more sensitive to O3; on the contrary, the α-Fe2O3–In2O3 (9:1) system, possesses a higher sensitivity to NO2. The optimal temperature for detecting of both gases is in the range of 70–100 °C. Sensors based on the γ-Fe2O3–In2O3 heterostructure show the maximum response to C2H5OH at considerably higher temperatures (250–300 °C), but these layers are practically insensitive to other reducing gases like CH4, CO and NH3 in the same temperature range. lanation of the different gas-sensitive behavior for these samples resulted from the particular features of their structure and phase state.