Gas sensor using gold doped copper oxide nanostructured thin films as modified cladding fiber

We investigate the spectral response of nanostructured copper oxides thin film. Gold was doped in two different concentrations(2% and 4%) using the spray method. A novel ammonia gas sensor at various concentrations(0–500 ppm)was fabricated by replacing CuO films with a clad region. In addition, the effect of gold doping on structural, optical,and morphological properties has been demonstrated. The study shows that the spectral intensity increases linearly with ammonia concentration. The 4% Au doped CuO presents higher sensitivity compared with 2% doped and pure copper oxides. Time response characteristics of the sensor are also reported.

Structural,Morphological and Electrical Properties of In-Doped Zinc Oxide Nanostructure Thin Films Grown on p-Type Gallium Nitride by Simultaneous Radio-Frequency Direct-Current Magnetron Co-Sputtering

Zinc oxide （ZnO） is one of the most promising and frequently used semiconductor materials. In-doped nanos- tructure ZnO thin films are grown on p-type gallium nitride substrates by employing the simultaneous rf and dc magnetron co-sputtering technique. The effect of In-doping on structural, morphological and electrical properties is studied. The different dopant concentrations are accomplished by varying the direct current power of the In target while keeping the fixed radio frequency power of the ZnO target through the co-sputtering deposition technique by using argon as the sputtering gas at ambient temperature. The structural analysis confirms that all the grown thin films preferentially orientate along the c-axis with the wurtzite hexagonal crystal structure without having any kind of In oxide phases. The presenting Zn, 0 and In elements＇ chemical compositions are identified with EDX mapping analysis of the deposited thin films and the calculated M ratio has been found to decrease with the increasing In power. The surface topographies of the grown thin films are examined with the atomic force microscope technique. The obtained results reveal that the grown film roughness increases with the In power. The Hall measurements ascertain that all the grown films have n-type conductivity and also the other electrical parameters such as resistivity,mobility and carrier concentration are analyzed.

Partial electrical potential distribution around nanospheres in metallic nanostructured films

In light of the nanostructured surface model, where half-spherical nanoparticles grow out symmetrically from a plane metallic film, the mathematical model for the partial electrical potential around nanospheres is developed when a uniform external electric field is applied. On the basis of these models, the three-dimensional spatial distribution of the partial electrical potential is obtained and given in the form of a curved surface using a numerical computation method. Our results show that the electrical potential distribution around the nanospheres exhibits an obvious geometrical symmetry. These results could serve as a reference for investigating many abnormal phenomena such as abnormal infrared effects, which are found when CO molecules are adsorbed on the surface of nanostructured transition metals.

Enhancing low-field magnetoresistance of La0.67Ca0.33MnO3 films deposited on anodized aluminium-oxide membranes

In this paper we report a new method to fabricate nanostructured films, La0.67Ca0.33MnO3 （LCMO） nanostructured films have been fabricated by using pulsed electron beam deposition （PED） on anodized aluminium oxide （AAO） membranes, The magnetic and electronic transport properties are investigated by using the Quantum Design physics properties measurement system （PPMS） and magnetic properties measurement system （MPMS）. The resistance peak temperature （Tp） is about 85 K and the Curie temperature （To） is about 250 K for the LCMO film on an AAO membrane with a pore diameter of 20nm. Large magnetoresistance ratio （MR） is observed near Tp. The MR is as high as 85% under 1 T magnetic field. The great enhancement of MR at low magnetic fields could be attributed to the lattice distortion and the grain boundary that are induced by the nanopores on the AAO membrane.

Investigation of the Surface Properties of Diamond-Like Carbon Films Using Multifractal Analysis

In this paper surface potential of DLC （diamond-like carbon） nanostructured film is studied. Fractal form of the surface of this film is discussed. Fractal parameters and surface potential as a function of them are calculated theoretically. Then obtained results are compared with the results measured by Kelvin probe method. The evolution of the surface topology and related surface potential during the deposition time is studied too. The dependence of multifractal parameters on the deposition duration was revealed.

Application of flame-formed carbon nanoparticle films for ethanol sensing Author links open overlay panel

Carbon nanoparticles(CNPs)have received considerable attention due to their exceptional qualities and adaptability.Their unique physical and chemical characteristics make them extremely intriguing as materials for numerous high-potential applications,such as electronics and gas sensing.This study focused on producing carbon-based nanomaterial devices by deposition of flame-formed carbon nanoparticles on a suitable substrate and investigating their gas-sensing properties.CNPs were produced in a fuel-rich laminar premixed ethylene/air flame and the collected CNP film was morphologically and electrically characterized.The electrical conductivity of the film was investigated as a function of ethanol concentration and amount of deposited material.Notably,CNP films exhibited high sensitivity to ambient ethanol gas concentrations,and rapid recovery times at room temperature,and showed a sensitivity increasing with the amount of deposited material and the surface complexity.Our findings demonstrate the high potential of combustion-generated CNPs as building materials for low-cost and portable ethanol sensors.

Frictional behavior of nanostructured carbon films

We propose a new path for preparing nanostructured carbon films(NCFs)by using electron cyclotron resonance(ECR)plasma sputtering with ion-electron hybrid irradiation for controlling the frictional behavior.The frictional behavior of the NCF was measured by using a pin-on-disk tribometer with a nanoprobe displacement sensor,and the transition curves of the friction coefficient and microdisplacement of the NCFs were examined.The friction mechanism was discussed by transmission electron microscopy(TEM)observation on the wear track.From the results,we found a new method to prepare NCFs,which has the potential to achieve low friction at the early stage of sliding contact.In addition,the technology of ECR plasma with ion-electron hybrid irradiation provides a new vision to rebuild a nanostructured surface from an original surface for controlling the frictional behavior.

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quan- titatively estimate the interfacial energy of the nanostructured multilayer films （NMFs） adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be ~ 5.0 J/m2 for Cu/Cr, ~4.1 J/m2 for Cu/Ta, ~ 2.8 J/m2 for Cu/Mo, ~ 1.1 J/m2 for Cu/Nb, and ~ 1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.

The Gas Nucleation Process Study of Anatase TiO_2 in Atmospheric Non-Thermal Plasma Enhanced Chemical Vapor Deposition

Abstract The gas phase nucleation process of anatase TiO2 in atmospheric non-thermal plasma enhanced chemical vapor deposition is studied. The particles synthesized in the plasma gas phase at different power density were collected outside of the reactor. The structure of the collected particles has been investigated by field scanning electron microscope （FESEM）, X-ray diffraction （XRD）, high resolution transmission electron microscopy （HRTEM） and selected area electron diffraction （SAED）. The analysis shows that uniform crystalline nuclei with average size of several nanometers have been formed in the scale of micro second through this reactive atmo- spheric plasma gas process. The crystallinity of the nanoparticles increases with power density. The high density of crystalline nanonuclei in the plasma gas phase and the low gas temperature are beneficial to the fast deposition of the 3D porous anatase TiO2 film.

Properties of fluorescence based on the immobilization of graphene oxide quantum dots in nanostructured porous silicon films

The fluorescence of graphene oxide quantum dots （GOQDs） that are infiltrated into porous silicon （PSi） is investigated. By dropping activated GOQDs solution onto silanized PSi samples, GOQDs are successfully in- filtrated into a PSi device. The results indicate that the intensity of the fluorescence of the GOQD-inflltrated multilayer with a high reflection band located at its fluorescence spectra scope is approximately double that of the single layer sample. This indicates that the multilayer GOQD-infiltrated PSi substrate is a suitable material for the preparation of sensitive photoluminescence biosensors.

Optical and structural properties of sol-gel derived nanostructured CeO_2 film

Sol-gel derived nanostructured CeO_2 film was deposited on glass substrate using by dip-coating technique with annealing at 650℃.X-ray diffraction（XRD）,scanning electron microscopy（SEM）,Fourier transform infrared （FTIR）,UV/vis and photoluminescence（PL） spectroscopy studies were employed to analyze the structural and optical properties of the sol-gel derived nanostructured CeO_2 film.The average crystallite size was estimated from the XRD pattern using by Scherrer equation as about 3-4 nm.An SEM micrograph shows that the film was porous in nature and crack free.The UV-visible absorption spectroscopic measurement results showed that the products had conspicuous quantum size effects.The absorption spectrum indicates that the sol-gel derived nanostructured CeO_2 film has a direct bandgap of 3.23 eV and the photoluminescence spectra of the film show a strong band at 378 nm：it may have a promising application as an optoelectronic material.

Layer Thickness-Dependent Hardness and Strain Rate Sensitivity of Cu–Al/Al Nanostructured Multilayers

Cu-Al/Al nanostructured metallic multilayers with Al layer thickness hAl varying from 5 to 100 nm were prepared, and their mechanical properties and deformation behaviors were studied by nanoindentation testing. The results showed that the hardness increased drastically with decreasing hAl down to about 20 nm, whereafter the hardness reached a plateau that approaches the hardness of the alloyed Cu-Al monolithic thin films. The strain rate sensitivity （SRS, m）, however, decreased monotonically with reducing hAl. The layer thickness-dependent strengthening mechanisms were discussed, and it was revealed that the alloyed Cu-Al nanolayers dominated at hAl≤ 20 nm, while the crystalline Al nanolayers dominated at hAl 〉 20 nm. The plastic deformation was mainly related to the ductile Al nanolayers, which was responsible for the monotonic evolution of SRS with hAl. In addition, the hAFdependent hardness and SRS were quanti- tatively modeled in light of the strengthening mechanisms at different length scales.

Novel Synthesis of Ceramic Films

1 Results There is an increasing demand for producing high performance ceramic films at a reduced cost. This paper describes an innovative and cost-effective method of producing nanostructured ceramic films based on Electrostatic Spray Assisted Vapour Deposition (ESAVD). ESAVD is a variant of chemical vapour deposition process which involves spraying atomised charged precursor droplets across an electric field where the precursor undergo decomposition and heterogeneous chemical reaction near the heat...

Effect of Annealing Temperature on the Morphology and Sensitivity of the Zinc Oxide Nanorods-Based Methane Senor

ZnO nanorods in the form of thin films were synthesized by a facile chemical route and the effect of annealing temperature on the structure and sensitivity of such ZnO-based sensors was studied in detail towards methane sensing.Morphological analyses of such films were carried out by scanning electron microscopy,whereas,the crystalline structure and phase purity of the films were analysed by X-ray diffraction technique.The films were observed to display a gradual change in their morphology from granular to dense nanorods and each of them was used to fabricate methane sensor prototype.They were also tested for temperature-dependent methane-sensing capability with varying methane concentrations.The optimized sensor exhibited highest gas response of ＊80% at 250 °C with significantly low response and recovery time.