Structural and gas-sensing characterization of tungsten oxide nanorods and nanoparticles

In this work we report on the preparation by Pulsed Laser Deposition (PLD) of tungsten oxide layers featuring different morphologies, dominated by either nanoparticles or nanorods, with the aim to investigate the different gas-sensing properties of these nanostructures. A detailed structural analysis is reported showing morphological stability of the films under thermal annealing and phase transition. Emphasis is also given to the characterization of networking connections of the prepared layers, determinant for the electrical properties of the chemiresistor devices. Results show that samples with nanorod morphology exhibit an increased specific sensitivity to ammonia. The higher sensitivity of nanoparticles to other compounds such as ethanol or acetone suggests that these complementary sensitivities can be exploited to obtain selective gas detection in electronic nose systems. (C) 2010 Elsevier B.V. All rights reserved.