Nanowires of metal oxides for gas sensing applications

Abstract

Nanowires of different metal oxides (SnO 2 , ZnO) have been grown by evaporation-condensation process. Their chemical composition has been investigated by using XPS. The standard XPS quantification through main photoelectron peaks, modified Auger parameter and valence band spectra were examined for the accurate determination of oxidation state of metals in the nanowires.Morphological investigation has been conducted by acquiring and analyzing the SEM images. For the simulation of working conditions of sensor, the samples were annealed in ultra high vacuum (UHV) up to 500 • C and XPS analysis repeated after this treatment. Finally, the nanowires of SnO 2 have were used to produce a novel gas sensor based on Pt/oxide/SiC structure and operating as Schottky diode.

Near-infrared optical constants and optical polarization properties of ZnO thin films

“…While the higher energy peak at binding energy of 531.94 eV has been interpreted as defect oxygen [44] or the oxygen containing surface contaminants [45]. The surface − OH may also contribute to the peak at this binding energy which indicates the presence of adsorbed hydroxide or surface contamination [45]. Moreover, indicates that the surfaces are smooth as well as a very good homogeneity of the deposited films.…”

“…The lower energy peak contributed to the O− ions in the ZnO lattice and is surrounded by Zn ions and hence indicates the bonding of ZnO. While the higher energy peak at binding energy of 531.94 eV has been interpreted as defect oxygen [44] or the oxygen containing surface contaminants [45]. The surface − OH may also contribute to the peak at this binding energy which indicates the presence of adsorbed hydroxide or surface contamination [45].…”

Ordered arrays of FePt nanoparticles on unoxidized silicon surface by wet chemistry

“…FePt nanoparticles were prepared from the redox reaction between Pt(acac) 2 and Na 2 Fe(CO) 4 , as reported by Howard et al [3]. Equimolar amounts (0.2 mmol) of the reagents and the surfactants (oleic acid and oleylamine) were added in nonadecane (13 ml) under nitrogen atmosphere.…”

“…XPS spectra were collected using an Escalab Mk II spectrometer (VG Scientific, UK); experimental details have been reported elsewhere [4]. The IR spectra were recorded with a BIORAD FTS-40A spectrometer.…”

Optical coupling between two nanobelts

“…For both application and fundamental purpose, it is worth to studying the light transmission in nanoscale. Up to now, nanobelts have been investigated in many areas, such as nanolasers [1,2], nanosensors [3], field effect transistors [4], etc. They are also good candidates as optical dielectric waveguides and components in integrated optics for their excellent waveguide effect [5][6][7].…”