Nano Thin Film Research Articles

Enhanced Terahertz Emission from CuxO/Metal Thin Film Deposited on Columnar-Structured Porous Silicon

Abstract We propose a novel method to enhance the THz emission from CuxO/metal nano thin film by using columnar-structured microsized porous silicon (MS-PSi) as the substrate. THz emission was improved several times higher than that from the planar substrate due to the decreased optical reflectance and enlarged surface area.

Pulsed Laser Deposited Sns-Snse Composite Thin Film As a New Anode Material for Lithium Storage

In recent years tin-based materials has been subjected as promising anode materials due to a high theoretical capacity of Li4.4Sn (994mAh g-1). However, tin-based materials is still far away from practical use since it suffers from significant volume change. It has been demonstrated that nano-thin film have its unique characteristics than bulk materials. In this work, SnS-SnSe composite thin films are synthesized by plused laser deposition. Its first discharge capacity was 1225.8 mAh g-1 and capacity after three cycles maintained about 650 mAh g-1. SnS-SnSe composite thin film firstly reacted with Li during discharge to form Li2SALi2Se and Sn, then Sn reacted with Li to form LixSn alloy. During the charge, LixSn firstly decomposed to form elementary Sn, then Sn catalyzed Li2S and Li2Se to decompose to rebuild SnS-SnSe composite thin film. Li2S and Li2Se produced during discharge can suffer a certain amount of volume change which enhanced the cycle performance. SnS-SnSe composite thin film had more grain boundary than SnS or SnSe thin film which could effectively enhance electrochemical activity and increase capacity. Fig.1 The first three CVs of SnS-SnSe composite thin film Fig.2 Galvanostatic charge-discharge curve of SnS-SnSe composite thin film electrodes Fig.3 Cycling performance of SnS-SnSe, SnS and SnSe thin films with 20 cycles Acknowledgements The authors appreciate the financial support of LPMT, CAEP (ZZ13007), Project 2013A030214 supported by CAEP. Figure 1

The evaluation of nanotribological property of nano thin film under different environment by atomic force microscopy

This study was based on an atomic force microscopy (AFM) to study the nanotribological property of Cr---N---Cu nanocomposite thin film under air and deionized (DI) water environment. Using the force curve test to get the normal force of probe, and the friction force was measured by the loop method. And then nanotribological experiments can be carried out under air and deionized (DI) water environment by a AFM. After Nanotribological experiments, we found that the coefficient of friction (COF) value of Cr---Cu---N nanocomposite thin film in DI water is significantly higher than that in air. And it can be found that whether in the air or DI water, the tip speed increases, the COF value decreases. In the air, the normal force increases, the COF value also increases, but, a different trend is observed in DI water.

Manufacture of Coated Cotton Fabric Anti-bacterial Nano Thin Film by Sequential Immersion – Sol- Gel Technique

Manufacture of Coated Cotton Fabric Anti-bacterial Nano Thin Film by Sequential Immersion – Sol- Gel Technique

Low Temperature Synthesis of Sub-micrometer Yttria-doped Barium Zirconate Thin Films by Modified Chemical Solution Deposition Technique

Yttria-doped barium zirconate (BZY) electrolyte films with sub-micrometer thickness were prepared using a modified chemical solution deposition (CSD) technique at very low sintering temperature of 800 °C without sintering aid. Pure perovskite BZY phase without barium carbonate associated with low calcination temperature was successfully obtained with no obvious barium (Ba) evaporation to deviate the stoichiometry composition. This cost effective and scalable method for BYZ as compared to the other reported vacuum-based thin film deposition techniques such as pulsed laser deposition (PLD) or atomic layer deposition (ALD) are potentially applicable in the fabrication of high quality electrolyte for nano-thin film micro solid oxide fuel cells operating at temperature below 500 °C.

Preparation and performance of Cu2O/TiO2 nano-thin film for photocatalytic degradation of methylene blue

Cu2O/TiO2 thin film is obtained by electrodeposition method. The structure and optical properties of thin film are characterised using X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), SEM, Raman, PL and ultraviolet visible spectrophotometer (UV-Vis). Photocatalytic performance of Cu2O/TiO2 thin film and degradation pathways for methylene blue (MB) is also investigated in this paper. The results indicate that the pure Cu2O/TiO2 thin film with the (111) preferential orientation shows a high photocatalytic activity, whose crystal structure exhibits high quality and is characterised by novel Raman optical properties of nanometre spherical morphology. PL and UV-Vis results indicate that Cu2O/TiO2 thin film has an obvious absorption and photoelectric response at the visible light range. After 300°C annealing treatment for the film, the intensity peak of (111) crystal plane and UV-Vis absorption intensity have enhanced 60 and 50%, respectively. The reaction rate constant and photoluminescence intensity are 2.8 and 3.4 times as high as those before annealing treatment. The separated efficiency of electron-hole pairs is increased. More than 99.9% of MB can be degraded in 3 h by Cu2O/TiO2 thin film. Moreover, MB molecule can be decomposed completely. Recycling use of the catalyst has revealed that the film can be reused for 18 times.

A miniature chemiresistor sensor for carbon dioxide

A carpet-like nanostructure of polyaniline (PANI) nanothin film functionalized with poly(ethyleneimine), PEI, was used as a miniature chemiresistor sensor for detection of CO2 at room temperature. Good sensing performance was observed upon exposing the PEI–PANI device to 50–5000ppm CO2 in presence of humidity with negligible interference from ammonia, carbon monoxide, methane and nitrogen dioxide. The sensing mechanism relied on acid–base reaction, CO2 dissolution and amine-catalyzed hydration that yielded carbamates and carbonic acid for a subsequent pH detection. The sensing device showed reliable results in detecting an unknown concentration of CO2 in air.

The photovoltaic efficiency of the fabrication of copolymer P3HT:PCBM on different thickness nano-anatase titania as solar cell

Organic solar cells based on (3-hexylthiophene):[6,6]-phenyl C61-butyric acid methylester (P3HT:PCBM) bulk heterojunction (BHJ) with an inverted structure have been fabricated using nano-anatase crystalline titanium dioxide (TiO2) as their electron transport layer, which was prepared on the indium tin oxide coated glass (ITO–glass), silicon wafer and glass substrates by sol–gel method at different spin speed by using spin-coating (1000, 2000 and 3000rpm) for nano-thin film 58, 75 and 90nm respectively. The effect of thickness on the surface morphology and optical properties of TiO2 layer were investigated by atomic force microscopy (AFM), X-ray diffraction and UV–visible spectrophotometer. The optical band gap of the films has been found to be in the range 3.63–3.96eV for allowed direct transition and to be in the range 3.23–3.69eV for forbidden direct transition to the different TiO2 thickness. The samples were examined to feature current and voltages darkness and light extraction efficiency of the solar cell where they were getting the highest open-circuit voltage, Voc, and power conversion efficiency were 0.66% and 0.39% fabricated with 90nm respectively.

Deposition and Characterization of CdS Nano Thin Film with Complexing Agent Triethanolamine

The equimolar concentration thin films of Cadmium Sulfide (CdxSx) with the complexing agent TEA were deposited on a glass substrate by the SILAR technique. The crystalline nature with face centered cubic crystal system of the CdS films is determined from X-ray diffraction analysis. The broadened diffraction peaks indicated nano sized particles of the film materials. The surface morphology of the films was studied by SEM analysis. The Energy Dispersive Analysis of X-ray (EDAX) plot confirms the equimolar composition of Cd and S ions in the film materials. Surface topography of the film was studied by AFM. The optical characteristic of absorbance, transmittance and band gap was analyzed by UV-visible spectra. The band gap energy of the material was observed as 2.18 eV and chemical bonding was studied by FT-IR spectral analysis.

Effect of pore depth on tribological behavior of anodic alumina films under nano-thin film lubrication

Abstract A number of parameters such as the dimple depth, dimple area density, and dimple shape, affect the tribological performance of dimpled surfaces, and a comprehensive tribological characterization of the depth-dependent nature of their material properties would be useful. However, only surfaces with dimples with depth-to-diameter ratios lower than 1 have been investigated. In this study, porous anodic alumina (PAA) films with high pore depth (PDEP)-to-pore diameter (PDIA) ratios (approximately 2.8–30) were prepared. The as-prepared films had the same PDIA value (50 nm) but different PDEP values (140 nm, 350 nm, 700 nm, 1100 nm, and 1500 nm). Perfluoropolyether was used as the lubricant to improve the tribological properties of the as-prepared films. The effects of the PDEP value on the tribological properties of the as-prepared films were investigated systematically. It was found that the antiwear performance of the PAA films was closely related to the combined effects of flexibility, mobility, and inherent lubricity of PFPE molecules and PDEP values in nanoporous structures as a reservoir for lubricants and wear particles. For PDEP-to-PDIA ratios greater than 1, under the conditions studied, the friction performance of the PAA films improved with an increase in the PDEP value. Further, after a critical PDEP value, the applied load had little effect on the friction coefficient and antiwear life of the films. The results of this study should aid the fabrication of stable films for industrial applications and act as a bridge between science and engineering on the micro/nanoscale.

P–P heterojunction sensor of self-assembled polyaniline nano-thin film/microstructure silicon array for NH3 detection

A novel P–P isotype heterojunction sensor was developed by modifying microstructure silicon array (MSSA) with self-assembled polyaniline (PANI) nano-thin film for ammonia (NH3) detection at room temperature, and the comparative study of response performance was focused on sensors with varied etching time of MSSA. The results indicated that PANI nanorods network was successfully deposited on MSSA surface, and PANI/MSSA sensor exhibited superior NH3-sensing properties than PANI/plane silicon sensor, which should be ascribed to three-dimensional structure and p-p heterojunction enhancement effect. Meanwhile, the optimized sensor with 4min etching time exhibited high response, good reversibility, repeatability and selectivity when exposed to NH3.

A circular membrane for nano thin film micro solid oxide fuel cells with enhanced mechanical stability

We demonstrate a new architecture for a low temperature solid oxide fuel cell to enlarge the lateral dimension of the fragile nano thin film electrolyte from the micrometer to millimeter scale with greatly enhanced mechanical stability.

Electronically type-sorted carbon nanotube-based electrochemical biosensors with glucose oxidase and dehydrogenase.

An electrochemical enzyme biosensor with electronically type-sorted (metallic and semiconducting) single-walled carbon nanotubes (SWNTs) for use in aqueous media is presented. This research investigates how the electronic types of SWNTs influence the amperometric response of enzyme biosensors. To conduct a clear evaluation, a simple layer-by-layer process based on a plasma-polymerized nano thin film (PPF) was adopted because a PPF is an inactive matrix that can form a well-defined nanostructure composed of SWNTs and enzyme. For a biosensor with the glucose oxidase (GOx) enzyme in the presence of oxygen, the response of a metallic SWNT-GOx electrode was 2 times larger than that of a semiconducting SWNT-GOx electrode. In contrast, in the absence of oxygen, the response of the semiconducting SWNT-GOx electrode was retained, whereas that of the metallic SWNT-GOx electrode was significantly reduced. This indicates that direct electron transfer occurred with the semiconducting SWNT-GOx electrode, whereas the metallic SWNT-GOx electrode was dominated by a hydrogen peroxide pathway caused by an enzymatic reaction. For a biosensor with the glucose dehydrogenase (GDH; oxygen-independent catalysis) enzyme, the response of the semiconducting SWNT-GDH electrode was 4 times larger than that of the metallic SWNT-GDH electrode. Electrochemical impedance spectroscopy was used to show that the semiconducting SWNT network has less resistance for electron transfer than the metallic SWNT network. Therefore, it was concluded that semiconducting SWNTs are more suitable than metallic SWNTs for electrochemical enzyme biosensors in terms of direct electron transfer as a detection mechanism. This study makes a valuable contribution toward the development of electrochemical biosensors that employ sorted SWNTs and various enzymes.

Photocatalytic degradation of cyanide in wastewater using new generated nano-thin film photocatalyst

This study investigates the possibility of using new generated potassium lanthanum titanates (K2La2Ti3O10, KLTO) photocatalyst thin films and CeO2 buffer layer produced using sol–gel method to remove cyanide from wastewater. DTA–TG, FTIR, XRD, XPS, SEM, AFM and profilometer analyses were performed to determine the thermal, structural and morphological characterization of the thin film photocatalysts, respectively. In order to provide the highest photocatalytic activity, new generated photocatalytic films with KLTO/CeO2 architecture were coated on Si (100) substrates and the cyanide degradation experiments were carried out. In this respect, initial concentration, pH of cyanide and light intensity were chosen as variables and their single and joint effects on removal of cyanide from wastewater were investigated. ATLAS Suntest CPS+ which simulates solar radiation was used as illumination source for the photocatalytic degradation of cyanide. ANOVA statistical test was carried out to understand the effectiveness of the variables. The degradation experiments were fitted to first order reaction law. The maximum degradation efficiency of cyanide was found to be 99.87% at pH of 10 and light intensity of 750W/m2 by using 100mg/l cyanide initial concentration after 5hour irradiation.

Characterization of porous silicon thin films passivated by a nano-silver layer

This study was performed to evaluate the effect of passivation of a nano thin film of silver (Ag) on the characterization of porous silicon (PS) surface. Silver nano layers of 10 and 20nm were deposited on a PS surface using RF-sputtering technique. The PS was prepared by electrochemical etching method (ECE) of n-type (111) Si in an electrolyte solution containing hydrofluoric acid (HF) and ethanol (C2H6O) at a volume ratio of 1:4 with direct current of 10 mA for 60min. Structural and optical characterizations of the PS samples before and after passivation carried out using Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-rays Analysis (EDX), X-ray Diffraction (XRD), reflectivity analysis using UV–vis spectrophotometer and photoluminescence (PL). These measurements show that Ag atoms regularity on the PS surface, whereas the Ag peaks confirm that increased deposition of Ag atoms on the PS surface also increases the thickness of the Ag film. The coated PS with a thin film of Ag (20nm Ag/PS) shows enhancement in the PL and reflectivity spectra. The highest PL of 20nm Ag/PS denotes the high electrical conductivity of Ag (63.01×106S/m) and the maximum reflectivity is attributed to the presence of surface plasmons resonance (SPR). As a result, Ag metal exhibits a negative dielectric constant at optical frequencies which leads to high reflectivity.

A tridentate (O, N, O) donor Schiff base zinc(II) nano complex

A nano tridentate (O, N, O) donor Schiff base derived from salicylaldehyde and o-aminophenol (o-AP), 2-[[(2-hydroxyphenyl)imino]methyl]phenol (PIMP), and its nano Zinc(II) complex thin films, [Zn(PIMP)(H2O)]; ZnSB-1, are synthesized via Layer-by-Layer (LbL) self-assembly method at ambient temperatures. Elemental and metal analyses confirm a (1:1) ligand to metal stoichiometric ratio of ZnSB-1 nano complex. Scanning electron microscopy elucidates the nano nature of the self-assembled materials. Powder X-ray diffraction and SEM revealed an excellent crystallized nano ZnSB-1 complex. Fourier transform infrared spectra reveal the coordination nature between Zinc(II) and PIMP ligand in nano ZnSB-1 complex. Electron impact mass spectra and thermogravimetric analysis (TG) studies confirm the chemical structure of LbL self-assembled nano materials. TG/DTG studies also show an increase in the thermal stability of the ZnSB-1 nano complex over its nano PIMP precursor. The favorable conditions for ZnSB-1 nano thin film assembly are focused and studied through tuning a number of different parameters.

Enhanced sensitivity of surface plasmon resonance phase-interrogation biosensor by using oblique deposited silver nanorods.

Sensitivity of surface plasmon resonance phase-interrogation biosensor is demonstrated to be enhanced by oblique deposited silver nanorods. Silver nanorods are thermally deposited on silver nanothin film by oblique angle deposition (OAD). The length of the nanorods can be tuned by controlling the deposition parameters of thermal deposition. By measuring the phase difference between the p and s waves of surface plasmon resonance heterodyne interferometer with different wavelength of incident light, we have demonstrated that maximum sensitivity of glucose detection down to 7.1 × 10-8 refractive index units could be achieved with optimal deposition parameters of silver nanorods.

Fabrication and characterization of highly sensitive ZnO/Si SAW device with Pd selective layer for F2 gas sensing

In this paper, ZnO nano thin film is prepared on n-type Si substrate with orientation using RF sputtering technique and a surface acoustic wave (SAW) based fluorine (F2) gas sensor integrated on ZnO with Palladium (Pd) on top as sensing layer is fabricated and characterized. The input and output interdigital transducer is fabricated of aluminum (Al) using nanolithography technique. The morphological characterization of ZnO thin film is done using scanning electron microscopy and atomic force microscopy. The XRD confirms the formation of ZnO nanostructured thin film. The voltage handling capability of the fabricated device is evaluated with negative and positive bias voltage. The study confirms that the SAW sensor based on ZnO/Si substrate and Pd sensing layer has good characteristic response of F2 gas with different concentration of gas from 0.5 to 20 ppm. The sensor shows good reproducibility and its sensitivity is approximately 2.4 kHz ppm?1.

Experimental and Numerical Evaluation on Optical Properties of Al‐Doped ZnO Film Materials

The aim of this article is to provide a systematic method to perform numerical and experimental evaluation on the optical properties of Al‐doped ZnO nano thin films. Some different doping density samples are deposited for testing the transmittance. The results show that the transmittance of Al‐doped ZnO has a nonlinear relation with the optical constants and Al‐doped quantity. The optical band gap of the Al‐doped ZnO decreases with the Al doping quantity increasing. Meanwhile, the Maxwell‐Garnett (MG) theory is used to investigate the optical properties of Al‐doped ZnO nano thin films in visible range. The comparison can illustrate the validity of both test and design method. It implies a potential design and evaluation method for developing a new type of ceramic nano thin film in engineering.

InSe Nanothin Film with Ar-Gas Low Vacuum Pressure

InxSe1-x(x = 0.4, 0.5, 0.6) thin films are deposited at room temperature on glass substrates with thickness ~500nm by thermal evaporation technique. The X-Ray diffraction analysis showed that both the as-deposited films In2Se3and InSe (x= 0.4 and 0.5) are amorphous in nature while the as-deposited film In3Se2is polycrystalline and the values of energy gap are Eg=1.44eV for In2Se3, Eg=1.16eV for InSe and Eg=0.78eV for In3Se2. The same technique used with insert Argon gas at pressure 0.1 mbar where InxSe1-x(x = 0.4, 0.5, 0.6) thin films are deposited at room temperature on glass substrates with thickness ~100nm. The X-Ray diffraction analysis showed that the as-deposited films In2Se3are amorphous in nature while the as-deposited film InSe and In3Se2are Nanocrystalline with grain size 33nm and 55nm respectively and the values of energy gap are Eg=1.55eV for InSe and Eg=1.28eV for In3Se2. The energy gap of InSe thin films increase with Argon gas assist and phases changes from amorphous and polycrystalline to nanostructure material by thermal vacuum deposition technique.