Functionalized vertical InAs nanowire arrays for gas sensing

Vertical InAs nanowires are contacted in situ using an air-bridge construction and functionalized with a metalloporphyrin (Hemin). The response of bare and functionalized vertical InAs nanowire arrays to ppb-level concentrations of NO2 and NO is demonstrated. Hemin enhances the response to NO whereas NO2 is also detected without...

Toward a minituarized low-power micromechanical electronic nose

An electronic nose based on an array of vibrating doubly clamped beams is proposed. These very high aspect ratio (length/thickness) suspended resonators can be individually functionalized by applying polymer coatings with an inkjet printing approach. The absorption of volatile compounds induces a swelling of the polymers that result in axial...

Comparison of nitric oxide binding to different pure and mixed protoporphyrin IX monolayers

The nitric oxide (NO) binding properties of monolayers of four different protoporphyrins IX adsorbed on aluminum oxide surfaces have been investigated. XPS and AFM results are consistent with the presence of a monolayer of porphyrins, bound to the surface by their carboxylic acid groups and with the porphine ring oriented more or less...

Sensitivity enhancement of metal oxide thin film transistor with back gate biasing

In this work, a room-temperature sensing device for detecting carbon monoxide using a ZnO thin film is presented. The ZnO layer (thickness close to the Debye length), which has a polycrystalline structure, is deposited with atomic-layer deposition (ALD) on an Al2O3/Si substrate. The operating principle of the sensor is based on measuring...

Enhancing the gas sensitivity of surface plasmon resonance with a nanoporous silica matrix

The development of sensing schemes for the detection of health-threatening gases is an attractive subject for research towards novel integrated autonomous sensor systems. We report here on a novel way of sensing NO\2 by surface plasmon resonance (SPR) using a gas-sensitive layer composed of 5,10,15,20-Tetrakis(4-hydroxyphenyl)-21H,23H-porphine ...

Universal scaling of the figure of merit of plasmonic sensors

We demonstrate an improvement by more than 1 order of magnitude of the figure of merit (FoM) of plasmonic nanoparticle sensors by means of the diffractive coupling of localized surface plasmon resonances. The coupling in arrays of nanoparticles leads to Fano resonances with narrow line widths known as surface lattice resonances, which are very...

Plasmonic Au islands on polymer nanopillars

The refractive index sensitivity of localized surface plasmon resonance sensors can be improved by placing the plasmonic metal particles on pillars instead of on a planar substrate. In this paper, a simple and versatile colloidal lithography method for the fabrication of plasmonic Au islands on top of polymer nanopillars is described. The pillar...

Gas sensing with AlGaN/GaN 2DEG channels

AlGaN/GaN shows great promise as a generic platform for (bio-)chemical sensing because of its robustness and intrinsic sensitivity to surface charge or dipoles. Here, we employ the two-dimensional electron gas (2DEG) formed at the interface of AlGaN/GaN layers grown on Si substrates for the ultra-sensitive detection of NOx. In the presence of...

Ionic-liquid based electrochemical ethylene sensor

We present an electrochemical ethylene sensor that exploits a thin ionic-liquid (IL) layer as electrolyte. ILs are fluids that completely consist of ions at room temperature and have emerged as extremely promising electrolytes for the following reasons: first, the vapor pressure is practically negligible and therefore even thin films remain...

Design, fabrication and characterization of electrostatic micro actuators for microfluidic platforms

Microfluidic devices for lab-on-a-chip applications have become obvious in the past decade. Often, small amounts of liquids need to be handled accurately and at a low power cost. Especially when autonomy is desired, the presence of on-chip micro actuators becomes obvious. In this paper, a novel family of microfluidic devices based on the...

High performance surface plasmon resonance sensor based on two dimensional ultra-thin metal nanoslit arrays

We present a high performance surface plasmon resonance (SPR) sensor based on two dimensional (2D) ultra-thin (40 nm) gold nanoslit arrays. These structures were designed to exhibit narrow linewidth (FWHM) and high transmission SPR under non-polarized illumination. In addition, we show the influence of the geometrical design on the performance...

Active control of the strong coupling regime between porphyrin excitons and surface plasmon polaritons

We experimentally demonstrate the active control of the coupling strength between porphyrin dyes and surface plasmon polaritons supported by a thin gold layer. This control is externally exerted by a gas flow and is reversible. The hybridized exciton-polariton branches resulting from the exciton-plasmon coupling display a splitting proportional...

Gas sensing with vertical functionalized InAs nanowire arrays

Nanowires show great promise for use in next generation (bio-)chemical sensing devices because of their high surface to volume ratio enabling efficient modulation of their current by charges or dipoles present at the surface. Here, we present a gas sensing device based on vertical InAs nanowire arrays grown without metal catalyst particles. The...

Ultralow-power hydrogen sensing with single palladium nanowires

Palladium nanowires were fabricated on silicon substrates using conventional microfabrication techniques. Sensors based on such nanowires show a reversible response to hydrogen concentrations as low as 27 ppm with response times varying from 5 s (H2 concentrations >20%) to 30 s (H2 concentrations <100 ppm) at room temperature. The response times...