Operating temperature dependent ethanol and formaldehyde detection of spray deposited mixed CdO and MnO2 thin films

Abstract

CdO–MnO₂ mixed oxide films are synthesized using a spray pyrolysis method. The structural study confirms the polycrystalline nature of the film and also confirms that the films are in a mixed oxide state. The morphological study reveals that the crystallite size is around 30 nm to 40 nm in size with spherical morphology. Energy dispersive spectroscopy confirms the presence of cadmium, manganese and oxygen in a mixed oxide state. The prepared CdO–MnO₂ film is highly sensitive to ethanol vapours at ambient temperature. The resistance of the film decreases drastically when it is exposed to ethanol and formaldehyde vapours. The prepared CdO–MnO₂ is highly sensitive to ethanol at ambient temperature and to formaldehyde vapour at 393 K. The sensitivity, selectivity, response time, recovery time and stability of the CdO–MnO₂ film towards ethanol and formaldehyde sensing are reported in the present work.