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Fabrication and characterization of ZnO nanostructures on Si(111) substrate using a thin AlN buffer layer
L.S. Chuah,
Z. Hassan,
S. K. Mohd Bakhori,
M. A. Ahmad,
Y. Yusof
Issue:
Volume 1, Issue 1, May 2013
Pages:
1-5
Received:
4 April 2013
Published:
20 May 2013
Abstract: In the present work, radio-frequency (RF) nitrogen plasma-assisted molecular beam epitaxy (PA-MBE) technique was used to grow AlN thin layers on Si(111) substrate. Subsequently, the thermal evaporation technique was used to deposit the zinc films on Si(111) substrates with AlN as buffer layer. ZnO nanostructures were obtained from zinc granulated (99.99%) by thermal oxidation from 400 °C to 600 °C in air for 1 hours without any catalysts. The effect of annealing temperatures were studied ranging from 400 °C to 600 °C in air for 1 hours. The AlN was introduced to accommodate the lattice mismatch and thermal expansion mismatch between ZnO layer and Si substrate. The structural and optical properties of ZnO nanostructures are studied through scanning electron microscopy (SEM), X-ray diffraction (XRD) and room temperature photoluminescence (PL) spectroscopy. The films show a polycrystalline hexagonal wurtzite structure without preferred (0002) orientation. The mean grain sizes are calculated to be about 18 nm, 22 nm and 50 nm for the ZnO films prepared at temperatures of 400 °C, 500 °C and 600 °C. The structure of the fabricated nanomaterials were characterized by scanning electron microscopy (SEM). The PL spectra of the ZnO nanostructures having a sharp excitonic ultraviolet (UV) emission and very weak defect-related deep level visible emissions. It is showed that the ZnO nanostructures thermal annealed treatment was performed at 600 °C shows the strongest UV emission intensity among the temperatures ranges studied. In addition, from the one-dimensional ZnO nanostructures thermal annealed at 600 °C, the stronger UV emission is assigned to the best crystalline quality of the ZnO film
Abstract: In the present work, radio-frequency (RF) nitrogen plasma-assisted molecular beam epitaxy (PA-MBE) technique was used to grow AlN thin layers on Si(111) substrate. Subsequently, the thermal evaporation technique was used to deposit the zinc films on Si(111) substrates with AlN as buffer layer. ZnO nanostructures were obtained from zinc granulated (...
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Study of Polymer Electrolyte for Zn Rechargeable Nanos-tructured Galvanic Cells via Combined in Situ SAXS/ DSC/ WAXD Measurements
A. Turković,
P. Dubček,
K. Juraić,
S. Bernstorff,
M. Buljan
Issue:
Volume 1, Issue 1, May 2013
Pages:
6-10
Received:
2 April 2013
Published:
30 May 2013
Abstract: Polymer electrolytes as nanostructured materials are very attractive components for batteries and opto-electronic devices. (PEO)8ZnCl2 polymer electrolytes were prepared from PEO and ZnCl2. The nanocomposites (PEO)8ZnCl2 themselves contained TiO2, Al2O3, MgO, ZnO and V2O5 nanograins. In this work, the influence of the Al2O3, MgO and V2O5 nanograins to the morphology and ionic conductivity of the nanocomposite was systematically studied by transmission small-angle X-ray scattering (SAXS) simultaneously recorded with wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) at the synchrotron ELETTRA. The SAXS/DSC/WAXD measurements yielded insight into the temperature-dependent changes of the grains of the electrolyte. The heating and cooling rate was 1°C/min and ½°C/min (1). Environment friendly galvanic cells as well as solar cells of the second generation are to be constructed with nanocomposite polymer as electrolyte.
Abstract: Polymer electrolytes as nanostructured materials are very attractive components for batteries and opto-electronic devices. (PEO)8ZnCl2 polymer electrolytes were prepared from PEO and ZnCl2. The nanocomposites (PEO)8ZnCl2 themselves contained TiO2, Al2O3, MgO, ZnO and V2O5 nanograins. In this work, the influence of the Al2O3, MgO and V2O5 nanograins...
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Dependence of Electron Beam Diameter, Electron Energy, Resist Thickness and Resist Type for Forming Nano-sized Dot Arrays in EB Lithography by Using Monte Carlo Simulation.
Hui Zhang,
Yulong Zhang,
Sumio Hosaka,
You Yin
Issue:
Volume 1, Issue 1, May 2013
Pages:
11-16
Received:
6 May 2013
Published:
30 May 2013
Abstract: We have calculated the electron energy deposition distribution in Calixarene negative resist and analyzed the development profile in order to improve the resolution of pattern. From the trajectories and energy deposition distribution in resist at various beam diameters, it is obvious that the thinner resist film should be adopted for formation of very fine dots. The analysis of relationship between the thickness of resist and dot diameter based on the critical energy densities shows that the thickness of resist less than 20 nm can obtain 5-nm size dot pattern at the range of critial energy of 6.25 keV/cm3-56.25 keV/cm3. The simulation of resist development profile indicates that dot size of 3 nm can even be obtained at a higher critical energy density at 156.25 keV/ cm3. Furthermore, Calixarene resist is more suitable than PMMA positive resist by comparison of these two resists
Abstract: We have calculated the electron energy deposition distribution in Calixarene negative resist and analyzed the development profile in order to improve the resolution of pattern. From the trajectories and energy deposition distribution in resist at various beam diameters, it is obvious that the thinner resist film should be adopted for formation of v...
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Fullerene C60 and its Derivatives as Nanocomposites in Polymer Nanofibres
Eva ZEMANOVÁ,
Eva KOŠŤÁKOVÁ,
Karel KLOUDA
Issue:
Volume 1, Issue 1, May 2013
Pages:
17-20
Received:
26 April 2013
Published:
10 June 2013
Abstract: This work describes the application of oxo-derivatives of fullerene C60 and pristine fullerene as a nanocomposite in polymerous nanofibres. In this work we used oxo- fullerene derivative, of which preparation was presented by the authors of the State office for nuclear safety (Prague) on Nanocon 2009 and on Nanocon 2010 [1, 2]; there was presented its application in vivo as a radioprotective agens. With respect to wild spectrum of potential utilization of unique chemical, structural a electron properties of fullerene we investigate its another possible technical application as nanocomposite in polymer nanofibres. The nanocomposite polymer nanofibers were produced by needle-less electrospinning method. Polyvinyl alcohol, polyurethane a polyvinyl butharate were used as polymers. Thermal resistance of obtained nanofibres without and with nanocomposites was tested by simultaneous thermogravimetric analysis and differential thermal analysis (TGA/DTA). The retarding influence of fullerene and its derivative on the course of the thermal decomposition of nanofibres is discussed.
Abstract: This work describes the application of oxo-derivatives of fullerene C60 and pristine fullerene as a nanocomposite in polymerous nanofibres. In this work we used oxo- fullerene derivative, of which preparation was presented by the authors of the State office for nuclear safety (Prague) on Nanocon 2009 and on Nanocon 2010 [1, 2]; there was presented ...
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Synthesis and Electrical Properties of TiO2 Nanoparticles Using a Wet Chemical Technique
Issue:
Volume 1, Issue 1, May 2013
Pages:
27-30
Received:
7 May 2013
Published:
10 June 2013
Abstract: TiO2 nanoparticles were synthesized using a wet chemical technique. The as prepared nanopowder was used for further characterization. The prepared TiO2 nanoparticles were characterized for phase composition, using X-ray diffractometry. The particle size and morphology were studied using Scanning electron microscope and transmission electron microscopy. The dielectric properties of TiO2 nanoparticles were studied in the different frequency range of 50Hz-5MHz at different temperatures. The frequency dependence of the dielectric constant and dielectric loss is found to decrease with an increase in the frequency at different temperatures. Further, the electronic properties like valence electron plasma energy, average energy gap or Penn gap, Fermi energy and electronic polarizability of the TiO2 nanoparticles were calculated.
Abstract: TiO2 nanoparticles were synthesized using a wet chemical technique. The as prepared nanopowder was used for further characterization. The prepared TiO2 nanoparticles were characterized for phase composition, using X-ray diffractometry. The particle size and morphology were studied using Scanning electron microscope and transmission electron microsc...
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A Nanoscale Investigation of Mechanical, Thermal Stability and Electrical Conductivity Properties of Reinforced Thermoplastic Polyurethane/Graphene Nanocomposite
Irene S. Fahim,
Wael Mamdouh,
Hanadi A. G. Salem
Issue:
Volume 1, Issue 1, May 2013
Pages:
31-40
Received:
9 May 2013
Published:
10 June 2013
Abstract: In the current research work reinforcement of a thermoplastic polyurethane (TPU) polymer with graphene powder (G, in the form of particles) as a nanofiller material by in-situ and ex-situ mixing of various weight fractions of G is reported. In addition, investigation on the effect of the weight fraction of G on the mechanical properties of the resulting TPU/graphene (TPU/G) nanocomposites is conducted. A number of different preparation methods have been employed in order to investigate the influence of the preparation process on the resulting TPU/G nanocomposites. Solvent (wet) mixing and mechanical (dry) mixing processes have been used. Significant enhancement in compressive strength, melt flow index and electrical conductivity were observed by employing the different mixing processes when compared with the pure TPU polymer processed under similar conditions. However, dry mixing process has shown enhanced mechanical, viscosity and electrical properties compared to wet mixing process. Moreover, dry mixing process has led to the formation of TPU/G nanocomposites with the highest compressive strength at 0.1 wt% G compared with 0.5, and 1 wt % G. It is believed that the processing technique plays a vital role in producing the desired TPU/G nanocomposites and is also affected by the dispersion of graphene nanofiller particles within the TPU polymer matrix. These results may lead to the development of novel applications of TPU/G nanocomposites across different disciplines.
Abstract: In the current research work reinforcement of a thermoplastic polyurethane (TPU) polymer with graphene powder (G, in the form of particles) as a nanofiller material by in-situ and ex-situ mixing of various weight fractions of G is reported. In addition, investigation on the effect of the weight fraction of G on the mechanical properties of the resu...
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Nanoparticles of Amorphous Cellulose and Their Properties
Issue:
Volume 1, Issue 1, May 2013
Pages:
41-45
Received:
10 May 2013
Published:
20 June 2013
Abstract: Method of preparation and some properties of amorphous cellulose nanoparticles (ANP) have been described in this paper. It was shown that ANP have spherical shape and are characterized by high degree of pantamorphia, low DP and increased content of sulfonic groups. The amorphous nanoparticles of cellulose are completely hydrolyzed by cellulolytic enzymes with forming of glucose. Concentrated paste of ANP has expressed thickening properties and therefore its additive can prevent phase separation of water dispersions of various substances. Low-acidic and soft nanoparticles can be used in cosmetic formulation for gentle skin peeling. Moreover, due to increased content of acidic functional groups, ANP can immobilize various therapeutically-active substances (TAS) containing basic functional groups. The ANP-TAS complexes can be used in remedies aimed for effective care and cure of the skin.
Abstract: Method of preparation and some properties of amorphous cellulose nanoparticles (ANP) have been described in this paper. It was shown that ANP have spherical shape and are characterized by high degree of pantamorphia, low DP and increased content of sulfonic groups. The amorphous nanoparticles of cellulose are completely hydrolyzed by cellulolytic e...
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