Atmospheric pressure fabrication of SnO2-nanowires for highly sensitive CO and CH4 detection

Köck, Anton; Tischner, Alexandra; Maier, Thomas; Kast, M.; Edtmaier, Christian; Gspan, Christian; Kothleitner, Gerald

doi:10.1016/j.snb.2009.02.055

Cited by 87 publications

(36 citation statements)

References 54 publications

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“…Recently, nanoscale field-effect biosensors [19][20][21]24] and gas sensors [16,22] have been demonstrated experimentally. A schematic diagram of such a sensor structure is shown in Fig.…”

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confidence: 99%

Multiscale modeling of fluctuations in stochastic elliptic PDE models of nanosensors

Heitzinger

Ringhofer

2014

Communications in Mathematical Sciences

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Abstract. In this work, the multiscale problem of modeling fluctuations in boundary layers in stochastic elliptic partial differential equations is solved by homogenization. Homogenized equations for the covariance and variance of the solution of stochastic elliptic PDEs are derived. In addition to the homogenized equations, a scaling law for the covariance and variance as the cell size tends to zero is given. For the homogenized problems, existence and uniqueness results and a priori bounds are given and further properties are proven. The multiscale problem stems from the modeling of the electrostatics in nanoscale field-effect sensors, where the fluctuations arise from randomly distributed charge concentrations in the cells of a boundary layer. Finally, numerical results and a spectral approximation are presented. 1. Introduction. The motivation for the present study of stochastic elliptic pde stems from the desire to model field-effect nano-sensors and hence to understand their physics. Elliptic equations, such as the Poisson equation and the linearized Poisson-Boltzmann equation, are the basic equations for their electrostatics, and the stochastic equations considered here make it possible to study fluctuations and noise in nanostructures. Furthermore, a multiscale problem is inherent in these nanoscale structures and it is solved by homogenization.First, we introduce the physical problem. Recently, nanoscale field-effect biosensors [19][20][21]24] and gas sensors [16,22] have been demonstrated experimentally. A schematic diagram of such a sensor structure is shown in Fig. 1. The length scale of the biomolecules is in the Angstrom or nanometer range, whereas the length of the nanowire is in the micrometer range. This gives rise to a multiscale problem, since it is not possible to resolve both the boundary layer and the whole simulation domain using a single numerical grid.This simulation problem also gives rise to a stochastic problem, since binding and unbinding events (in the case of biosensors) or chemical reactions (in the case of gas sensors) occur in the boundary layer. Additionally, the movement of the molecules in the boundary layer can be modeled by calculating their electrostatic free energy and by using a Boltzmann distribution [11]. These effects imply that the charge

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“…Recently, nanoscale field-effect biosensors [19][20][21]24] and gas sensors [16,22] have been demonstrated experimentally. A schematic diagram of such a sensor structure is shown in Fig.…”

mentioning

confidence: 99%

Multiscale modeling of fluctuations in stochastic elliptic PDE models of nanosensors

Heitzinger

Ringhofer

2014

Communications in Mathematical Sciences

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“…deposition of nanocrystalline SnO 2 -films by spray pyrolysis, and b. a subsequent annealing process at 900 °C in Ar atmosphere [18][19][20][21].…”

Section: Synthesis Of Sno 2 and Cuo Nanowiresmentioning

confidence: 99%

Metal Oxide Nanowires for Gas Sensor Applications

Köck

Defregger

Kraker

et al. 2014

Berg Huettenmaenn Monatsh

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“…Nanomaterials have been extensively investigated for developing new gas sensors with high sensitivities and low working temperatures in the past decades. Various MOS nanostructures, including nanotubes [3,4], nanowires [5,6], and nanobelts [7], have been synthesized and explored for preparing such gas sensors. Although their sensitivities have been dramatically increased and their working temperatures have been considerably lowered even down to room temperature, all those sensors have not been commercialized for practical applications up to date due to some shortcomings inherent in low dimensional MOSs, such as low thermal stability and mechanical strength [8,9], strong adsorption of moisture [10], and difficulty in mass production.…”

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confidence: 99%

Gas sensing capabilities of TiO2 porous nanoceramics prepared through premature sintering

et al. 2015

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Pure and noble metal (Pt, Pd, and Au) doped TiO 2 nanoceramics have been prepared from TiO 2 nanoparticles through traditional pressing and sintering. For those samples sintered at 550 ℃, a typical premature sintering occurred, which led to the formation of a highly porous microstructure with a Brunauer-Emmett-Teller (BET) specific surface area of 23 m 2 /g. At room temperature, only Pt-doped samples showed obvious response to hydrogen, with sensitivities as high as ~500 for 1000 ppm H 2 in N 2 ; at 300 ℃, all samples showed obvious responses to CO, while the responses of noble metal doped samples were much higher than that of the undoped ones. The mechanism for the observed sensing capabilities has been discussed, in which the catalytic effect of Pt for hydrogen is believed responsible for the room-temperature hydrogen sensing capabilities, and the absence of glass frit as commonly used in commercial thick-film metal oxide gas sensors is related to the high sensitivities. It is proposed that much attention should be paid to metal oxide porous nanoceramics in developing gas sensors with high sensitivities and low working temperatures.

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Atmospheric pressure fabrication of SnO2-nanowires for highly sensitive CO and CH4 detection

Cited by 87 publications

References 54 publications

Multiscale modeling of fluctuations in stochastic elliptic PDE models of nanosensors

Multiscale modeling of fluctuations in stochastic elliptic PDE models of nanosensors

Metal Oxide Nanowires for Gas Sensor Applications

Gas sensing capabilities of TiO2 porous nanoceramics prepared through premature sintering

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