A Gradient Microarray Electronic Nose Based on Percolating SnO₂ Nanowire Sensing Elements

Abstract

Fabrication, characterization, and tests of the practical gradient microarray electronic nose with SnO(2) nanowire gas-sensing elements are reported. This novel device has demonstrated an excellent performance as a gas sensor and e-nose system capable of promptly detecting and reliably discriminating between several reducing gases in air at a ppb level of concentration. It has been found that, in addition to the temperature gradient across the nanowire layer, the density and morphological inhomogeneities of nanowire mats define the discriminating power of the electronic nose.

Semiconducting Sn3O4 nanobelts: Growth and electronic structure

“…Among them, oxide-based nanostructures deserve significant attention because of their unique combination of interesting structural, optical, and electronic properties, which make them a promise of smaller, faster, and cheaper nanodevices. SnO 2 is one of the most studied and used materials for the development of gas sensors, 1 transparent conductors 2 ͑high conductivity from oxygen vacancies or intentional doping͒, and catalysts. 3 The intermediary and nonstoichiometric SnO 2−x ͑0 Ͻ x Ͻ 1͒ compounds are hardly synthesized and the fewer experimental observations are only a result of nonintentional thermal oxidation of SnO and SnO 2 phases.…”

Insight into the Role of Oxygen Diffusion in the Sensing Mechanisms of SnO2 Nanowires

“…[1][2][3][4][5][6] In particular, chemical sensing is favored by their high surface-tovolume ratio. [4] In the last years, many groups have devoted their efforts to determine the ultimate sensing capabilities of these nanomaterials [1][2][3][4][5][6][7][8][9] and to obtain theoretical models able to describe their experimental responses. [3,4,6] On the other hand, present nanofabrication techniques enable the development of new prototypes which combine metal oxide nanowires with well-established microelectronic technologies.…”

“…SnO 2 nanowires are currently used as the building blocks of a new generation of gas sensors, and their properties are being examined in detail. [3,4,6,8,9,19] In this study, the interaction between oxygen species and individual SnO 2 nanowires was analyzed. As surface models are not enough to explain the changes of nanowires' electrical resistance R NW with different oxygen partial pressures, oxygen diffusion into the bulk is proposed to be the responsible for the long -term drifts of R NW after exposing the nanowires to changes of the oxygen partial pressure in air.…”

ZnO Quasi-1D Nanostructures: Synthesis, Modeling, and Properties for Applications in Conductometric Chemical Sensors

“…In a first approximation, it does not depend either on temperature or on gas adsorption/desorption phenomena. The sensor response to a reducing gas is expressed as follows [55]: …”