Direct observation of the gas-surface interaction kinetics in nanowires through pulsed self-heating assisted conductometric measurements

摘要

Dynamics of gas-surface interactions determine the limits of the fastest response times of sensors based on metal oxides. Here, the kinetics of adsorption and desorption of gaseous molecules onto the surface of metal oxide nanowires was analyzed through pulsed self-heating assisted conductometric measurements. This approach overcomes gas diffusion, which is typical of conventional porous film based devices, and provides thermal response times fast enough to evaluate the fundamental gas-surface reactions kinetics. Experimental response and recovery times of individual SnO_2 nanowires toward oxidizing and reducing gases obtained with the here-proposed methodology were related to the reaction barriers predicted by theoretical models and other experimental techniques.