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 based on the double-layers Fe2O3/In2O3 and Fe2O3-In2O3/In2O3 towards gases with different chemical nature (C2H5OH, CH4, CO, NH3, NO2, O3). As it was found, the -Fe2O3-In2O3 composite (Fe:In = 9:1) is more sensitive to O3; on the contrary, the -Fe2O3-In2O3 system (9:1), possesses an higher sensitivity to NO2. The optimal temperature for detecting both gases is in the range 70 - 100C. Sensors based on the -Fe2O3/In2O3 heterostructure show the maximum response to C2H5OH at considerably higher temperatures (250-300C), but this layer is practically insensitive to other reducing gases like CH4, CO and NH3 in the same temperature range. An explanation of the different gas-sensitive behavior for the these samples resulted from the particular features of their structure and phase stat