Gas sensing behaviour of mat-like networked tungsten oxide nanowire thin films

Here, we present the results of the resistive response of tungsten trioxide nanowire (mat-like, nanowire networks) and nanoparticle thin films subjected to N2O gas in the temperature range of 373-773 K. The nanowire mats exhibited an order of magnitude higher response in the resistivity change compared to that of nanoparticle films at temperatures above 523 K. Nanowire mats also exhibited relatively faster adsorption and desorption times. Impedance spectroscopy studies showed that the gas sensing mechanism for nanowire mats involves changes in both the nanowire and grain boundary resistances, whereas for nanoparticle films only the grain boundary resistance governs the sensor properties upon exposure to gases.