Effects of the Fe doping on the physical properties and LPG gas detection of Fe-doped SnO2 films deposited by DC sputtering

The capacity to manufacture gas sensing materials with excellent sensitivity at room temperature is a focus of many studies; which could reduce manufacturing costs and expand their applications. In this regard, iron-doped SnO2 films were successfully grown via DC sputtering technique in the present report. The structural characterization revealed the formation of the rutile-type SnO2 phase. The morphological characterization of these films indicated a columnar growth on the glass substrate. The optical characterization suggests the occurrence of tensile strain and quantum confinement effects related to the small crystallite size. Magnetization measurements show the presence of a room temperature long-range magnetic order contribution associated with crystal defects in the x = 0.00 and x = 0.01 Fe doped SnO2 films. That ferromagnetic contribution becomes weaker for the x = 0.02 Fe doped film likely due to the lower charge density after the Fe doping. The gas sensing tests, at room temperature, using LPG gas indicate that iron doping alters the gas sensing response of the undoped SnO2 film, due to the presence of p-type carriers likely located at the particles surface, leading to an opposite behavior to the undoped film.