STRUCTURAL AND GAS-SENSING PROPERTIES OF NANOMETER TIN OXIDE PREPAREDBY PECVD

A low-temperature plasma-enhanced chemical vapour deposition (PECVD) t echnique has been employed to produce ultrafine tin oxide powders. The structural features and phase transition of this material have been c haracterized using differential thermal analysis (DTA), thermogravimet ric analysis (TGA), X-ray diffraction, infrared spectroscopy (IR) and transmission electron microscopy (TEM). The oxygen absorption behaviou r and gas-sensing properties have been investigated by electron parama gnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS) and ele ctrical measurements. Thick film gas sensors made from such ultrafine SnO2 powders yield better sensitivities than those of normal undoped S nO2 gas sensors. A gas-sensing reaction mechanism is also proposed.