Effects of ultrasonic field in pulse electrodeposition of NiFe film on Cu substrate.

NiFe film was pulse electrodeposited on conductive Cu substrate under galvanostatic mode in the presence of an ultrasonic field. The NiFe film electrodeposited was subjected to structural and surface analyses by X-ray diffraction, energy dispersive X-ray spectroscopy, surface profiling and scanning electron microscopy, respectively. The results show that the ultrasonic field has significantly improved the surface roughness, reduced the spherical grain size in the range from 490–575 nm to 90–150 nm, and increased the Ni content from 76.08% to 79.74% in the NiFe film electrodeposited

Variation of Nd and Vfb for different compositions of CdSexTe1−x thin films by pulse plating technique

CdSexTe1-x thin films with 0 < x < 1 have been pulse electrodeposited oil titanium (Ti), nickel (Ni) and stainless-steel (SS) substrates with different duty cycles. The size of the particles could be controlled by the pulse parameters. The deposition was carried out at room temperature for I It under potentiostatic mode with CdSO4, SeO2, TeO2, and H2SO4 as precursors. As-deposited and annealed films coated on Ti, Ni and SS were characterized by X-ray diffraction technique and SEM, and their electrical properties were studied. The as-deposited films exhibited a cubic structure; those after heat treatment at 500 degrees C in air exhibited a hexagonal structure. Variation of donor concentration and the flat band potential for different values of 'x' and duty cycles were studied for CdSexTe1-x thin films. The semiconductor parameters for all compositions coated on Ti, Ni and SS were estimated. It showed good agreement with the earlier reports. (c) 2005 Elsevier B.V. All rights reserved

Importance of pulse reversal effect of CdSe thin films for optoelectronic devices

Systematic studies of cadmium selenide thin films were prepared by without and with pulse reversal plating technique. In the present work, preparation of CdSe thin films was reported with lower duty cycle and pulse reversal effect. Due to these effects electrical and opto-electronic property of the material were changed. The thin film of CdSe was deposited on cleaned conducting substrates like titanium, SnO2, nickel and stainless steel, respectively. The pulse plated CdSe films without and with pulse reversal films were heat treated and characterized by XRD, optical studies, scanning electron microscopy and photo electrochemical properties. Semiconductor parameters were estimated for without and with pulse plating technique. The barrier height Ob was calculated for CdSe deposited on different conducting substrates. (c) 2005 Elsevier B.V. All rights reserved

Simulated Dielectric Characteristics of Pt/BST/Ni-Fe/Cu Multilayer Capacitor Stack for Storage Application

In this simulation research work, the metal-composite-metal (MCM) multilayer capacitor structure [Pt/BST/Ni-Fe/Cu] is proposed with Barium Strontium Titanate (BST) oxide material as the capacitor dielectric material for DRAM with permalloy Nickel-Ferrous (Ni-Fe) coated Copper (Cu) as the bottom conducting electrode and platinum as the top conducting electrode. This proposed MCM consists of 120 pin Cu bottom contact material, a I pm of Ni-Fe alloy over the stoichiometric composition of the BST oxide dielectric material of thickness 40 nm and dielectric constant of 775. The MCM structure is expected to deliver a maximum charge storage capacity of 109.75 fF for a capacitor in DRAM cell area of 0.64 mu m(2) well above the minimum requirement for DRAM cell. The leakage current density for a variation of voltage from 0 to 10 V has been simulated for temperature variation. When compared with the previous report, the proposed multi layer capacitor (MLC) structure shows promising potentials in terms of dielectric characteristics

Rapid Crystallization by Microwave Heating for Barium Strontium Titanate Powders Prepared using Slow-Rate Sol-Gel Technique

In this research work, different compositional ratios of Barium Strontium Titanate [BST] powders have been prepared using slow-rate gellification by sol-gell route and ex-situ microwave heating method. The finely grinded powders prepared were analyzed using Thermo Gravity Analysis [TGA], Differential Thermal Analysis [DTA] and characterized by X-ray Diffractometer [XRD]. TGA result shows that the organic solvents and unwanted impurities were removed at 117.89 degrees C and decomposition of carbonate took place at 205.19 degrees C. In addition, the material for 0.5 M ratio of Barium acetate and Strontium acetate and I M of Titanium Iso-propoxide started crystallization at 438.93 degrees C to yield BST. From the DTA results, it was found that when the microwave heating time was increased from 10 minutes to 25 minutes, the temperature at which endothermic reaction occurs has been shifted to lower values from 110 degrees C to 83.413 degrees C. These values matched those of the TGA results. The crystalline size was estimated from FWHM result to be in the range of 70 nanometer. The major peaks in the XRD analysis of the sample correspond to (100), (110), (111) and (200) were obtained for BST and agreed with American Standard for Test Measurement [ASTM] data. The materials exhibited pollycrystalline pattern with "d" values that matched with standard reports

Photoluminescence properties of nanocrystalline ZnS on nanoporous silicon

This paper embodies the report on the microwave solvothermal synthesizing of nanocrystalline ZnS particles for optoelectronic device. The effect of different parameters such as time, temperature, solvents, molar ratio of zinc and thiourea on the phase(s) formation of nanocrystalline Zinc Sulphide was investigated. The obtained nanosize ZnS materials were characterized by the X-ray diffraction, Optical absorption measurements, TEM and. Photoluminescence studies. The crystallite size of the ZnS nanoparticles was estimated from the X-ray diffraction pattern by using Scherrer's formula. The as prepared material was obtained in the cubic phase, which showed a perfect match with the earlier reports. The Optical absorption edge of ZnS were blue shifted from the absorption edge of bulk ZnS. The estimated band gap value of ZnS was 4.01 eV. The ZnS nano materials were coated on nano porous silicon by screen-printing technique. Luminescence studies indicated room temperature emission in the wavelength ranges from 422.6 to 612 nm, which cover the blue emission to red emission. The emitted light that depending on the created pore size from porous silicon and the size of the ZnS nano particles. (c) 2006 Springer Science + Business Media, Inc

Photoluminescence studies of Eu[sup 3+] doped Y[sub 2]O[sub 3] nanophosphor prepared by microwave hydrothermal method

In this letter, the authors report the photoluminescence studies of Eu3+ doped Y2O3 nanorods, which have been synthesized by rapid microwave hydrothermal route within 6 min. The nanostructured Eu3+ doped Y2O3 is characterized by x-ray diffraction, transmission electron microscopy, and photoluminescence. The emission spectrum shows transitions from the excited 5D0 state to math (J = 0,1,2,3,4) levels of the Eu3+ ion. The most intense peak around 612 nm is due to the math→math transition, expected from the Judd-Ofelt selection rules [ B. R. Judd, Phys. Rev. 127, 750 (1962) ; G. S. Ofelt, J. Chem. Phys. 37, 511 (1962) ]. Photoluminescence measurements demonstrated that the nanocrystalline Eu3+:Y2O3 phase shows higher photoluminescence intensity

Novel approach to control CdS morphology by simple microwave-solvothermal method

Nanosize CdS powders with different microstructures are prepared in different solvents by using rapid microwave irradiation. Effect of solvents and Cd2+ precursors are to be able to control the particle size, and microstructures of CdS have been investigated by X-ray diffraction and TEM. The different particle size and morphologies are observed using different Cd2+ precursors in different solvents. TEM micrographs clearly show multiarmed nanorods and spherical shape morphologies of CdS powders are obtained in polar solvent like water (H2O), whereas non-polar polyol solvent like ethylene glycol (EG), prickle and cluster like morphologies of CdS are achieved with different Cd2+ precursors such as CdSO4 and Cd (CH3COO)(2). The spectroscopy studies of nanosize CdS are examined by photo-luminescence spectra. Band gap and the absorption co-efficient for nano CdS is also evaluated from optical absorption studies. (C) 2005 Springer Science + Business Media, Inc

Particle Size Analysis of Barium Titanate Powder by Slow-Rate Sol-Gel Process Route

In this research work, different compositional ratios of Barium Titanate [BT] powders have been prepared using slow-rate gellification by sol-gel route. The as-prepared materials have been calcinated at 300 degrees C for 8 hours to remove the presence of carbon, and subsequently annealed at 700 degrees C for one hour for the phase formation. After annealing, the finely grinded powders were characterized by X-Ray diffractometer [XRD], Atomic Force Microscope [AFM] and Nano particle size analyzer [NPSA]. The XRD pattern shows that the material was BT with polycrystalline phase. It exhibited tetragonal phase with crystalline size in the range of 97 nm. The lattice constants 'a' and 'c' were perfectly matched with the standard reports. The surface morphology study by AFM shows that the materials were homogenously fine grains. The average particle sizes reduce from 750 urn to 78.49 nm when the concentration of barium salt decreases. This observation clearly indicates that the tuning of the particle sizes is possible by controlling the compositional ratios of barium and titanium. The particle distributions of the samples have also been analyzed by nano particle size analyzer. In this work, samples with equal amount of barium and titanium exhibited particle size distribution down to 100 urn range, with good structural and morphological properties