1-D ZnO nano-assemblies by Plasma-CVD as chemical sensors for flammable and toxic gases

In this work, 1D ZnO nano-assemblies were prepared on Al2O3 substrates by plasma enhanced-chemical vapor deposition (PE-CVD), and characterized in their morphology and chemical composition by field emission-scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDXS) and X-ray photoelectron spectroscopy (XPS). For the first time, the sensing performances of PE-CVD ZnO nanosystems were tested in the detection of toxic/combustible gases (CO, H2 and CH4), revealing very good responses already at moderate working temperatures. In particular, carbon monoxide and hydrogen detection was possible already at 100 °C, whereas methane sensing required a minimum temperature of 200 °C. The performances of the present ZnO nanosystems, that make them attractive candidates for technological applications, are presented and discussed in terms of their unique and controllable morphological organization.