Nanosensors based on individual hybrid structures and their application in gas sensing at room temperature

Abstract

Because the commercialization of nanosensors in the field of gas sensing is still in its infancy, many efforts have been made to develop efficient methods to increase their performances. A special attention was paid to the increase of the sensitivity and selectivity of the gas nanosensors based on individual micro - or nanostructures using different strategies. In this work, the recent results in the field of high-performance gas nanosensors obtained by the research group from Centre for Nanotechnology and Nanosensors, Technical University of Moldova in collaboration with Kiel University, Germany are highlighted and summarized. The quasi-uni-dimensional (1-D) and three-dimensional (3-D) individual hybrid structures based on zinc oxide were integrated into nanodevices using a focused ion beam/scanning electron microscopy (FIB/SEM) instrument. The hybridization of the individual ZnO structures is shown to result in a considerable increase in gas response, as well as a change in selectivity to volatile organic compounds and ammonia. Particularly, an increase in hydrogen gas response (by about 2 times) was obtained by surface functionalization with ZnAl2O4 nanoparticles, while a change in selectivity to ethanol vapors and ammonia was obtained by surface functionalization with Fe2O3 nanoparticles or buckminster fullerenes (C60) and carbon nanotubes (CNTs), respectively. The obtained results provide new avenues for the rational engineering of gas nanosensors by the use of hybrid nanomaterial systems with enhanced synergistic catalytic behavior and potential barrier manipulation.