Selective Detection of Nitrogen-Containing Compound Gases.

N-containing gaseous compounds, such as trimethylamine (TMA), triethylamine (TEA), ammonia (NH), nitrogen monoxide (NO), and nitrogen dioxide (NO) exude irritating odors and are harmful to the human respiratory system at high concentrations. In this study, we investigated the sensing responses of five sensor materials-Al-doped ZnO (AZO) nanoparticles (NPs), Pt-loaded AZO NPs, a Pt-loaded WO (Pt-WO) thin film, an Au-loaded WO (Au-WO) thin film, and N-doped graphene-to the five aforementioned gases at a concentration of 10 parts per million (ppm). The ZnO- and WO-based materials exhibited n-type semiconducting behavior, and their responses to tertiary amines were significantly higher than those of nitric oxides.

SnO2 nanoslab as NO2 sensor: identification of the NO2 sensing mechanism on a SnO2 surface.

Among the various metal oxides, SnO2 has been most widely exploited as a semiconductor gas sensor for its excellent functionalities. Models illustrating the sensing mechanism of SnO2 have been proposed and tested to explain experimentally derived "power laws". The models, however, are often based on somewhat simplistic assumptions; for instance, the net charge transfer from an adsorbate to a sensor surface site is assumed to occur only by integer values independent of the crystallographic planes.

A surface acoustic wave-based immunosensing device using a nanocrystalline ZnO film on Si.

The novelty of this study resides in the fabrication of a bio-sensing device, based on the surface acoustic wave (SAW) on a nanocrystalline ZnO film. The ZnO film was deposited using an rf magnetron sputtering at room temperature on silicon. The deposited films showed the c-axis-oriented crystallite with grain size of approximately 40 nm.

Nanocrystalline ZnO film layer on silicon and its application to surface acoustic wave-based streaming.

A surface acoustic wave (SAW) device consisting of 1-6 microm-thick ZnO thin films deposited on Si wafer was designed, fabricated, and characterized in this study. Photolithographic protocols for interdigitated transducers (IDTs) and surface modification using fluoroalkylsilane are employed with the aim of droplet-based microfluidic actuations in bio-microsystems. A ZnO thin film was grown on a 4' silicon wafer with c-axis orientation, an average roughness of 11.

ZnO nanotips and nanorods on carbon nanotube/Si substrates: anomalous p-type like optical properties of undoped ZnO nanotips.

ZnO nanotips and nanorods were grown on screen-printed multi-walled carbon nanotube (MWCNT) films via thermal chemical vapor deposition at relative low growth temperatures of 400 and 500 °C. Uniform formation of ZnO nanotips and nanorods occurred on MWCNT-printed Si substrates, but were rarely observed on bare Si substrates at the same growth temperatures. In photoluminescence (PL) measurements, it was found that ZnO nanorods exhibit typical intrinsic optical properties, while ZnO nanotips revealed p-type like luminescence behavior.

On-chip deposition of carbon nanotubes using CMOS microhotplates.

The direct deposition of carbon nanotubes on CMOS microhotplates is demonstrated in this paper. Tungsten microhotplates, fabricated on thin SOI membranes aside CMOS control circuitry, are used to locally grow carbon nanotubes by chemical vapour deposition. Unlike bulk heating of the entire chip, which could cause degradation to CMOS devices and interconnects due to high growth temperatures in excess of 500 °C, this novel technique allows carbon nanotubes to be grown on-chip in localized regions.

Separation of apoptotic cells using a microfluidic device.

A highly sensitive microfluidic device has been developed to separate apoptotic cells. Apoptotic Jurkat cells were selectively labeled with magnetic beads (0.8 microm diam) using the C2A protein which recognizes phosphatidylserine.

Analysis of recombinant protein expression using localized surface plasmon resonance (LSPR).

The localized surface plasmon resonance (LSPR)-based optical biosensor using nano-structures of noble metals has been considered as a useful tool for label-free detection of DNA hybridization and protein-protein interactions. We fabricated LSPR-based optical biosensors using gold nano-islands (nominal thickness; 75 A) on glass substrates that were easily made using the conventional fabrication methods. The formation of gold nano-islands on glass substrates was realized by heat treatment of thin gold film deposited with a low deposition rate (approximately 0.