Chronoamperometry Study of the Electrodeposited Ni100-XPx Alloy Thin Films

2014 ◽  
Vol 605 ◽  
pp. 661-664
Author(s):  
Hadria Medouer ◽  
Chahira Benyekken ◽  
Saci Messaadi

Elecrodeposited Ni-P alloy thin films have been the subject of extended investigations, since the pioneering works of Brenner et al, in the late 1940s. It is well known, that the physical and chemical properties of the Ni-P deposit composition are strongly influenced by the preparation conditions. In our experimental procedure, we have used a Parstat 2253 potensiostat equipped with Power-Suite software. All the electrochemical experiments were performed in a three electrode cell in which the volume of the bath was 150ml, in this experimental technique, we can measure one or more of three parameters: the potential (V), current (i), and time (t). The aim of our work consists to study the nucleation and growth process and given morphology and composition of electrodeposited Nix-P100-xthin films on Copper substrates. For this purpose, cyclic voltametry and chnonoamperomaty have been used in order to determine the previous cited properties of thin films Ni-P, [0.10 of NaPH2O2solutions. The chrnoamperogramms can be interpreted by the use of one of three models called: Growth mode (Me layer by layer formation); Franck Van der Merwe, FM model, Growth mode 3D (Me island formation on the top of predeposited), 2D Meads overlayers on substrat and Stranski-Krastanov; (SK model).

MRS Bulletin ◽  
1996 ◽  
Vol 21 (4) ◽  
pp. 27-30 ◽  
Author(s):  
Christopher Roland

Strain relaxation in lattice-mismatched, heteroepitaxial systems is one of the classic problems in materials physics, which has gained new urgency with the increased applications of strained layers in microelectronic systems. In general both the structure and the integrity of the thin films are strongly influenced by strain. For instance it has long been known that under strain, the growth changes from an initial layer-by-layer growth mode to one with three-dimensional islanding. In the seminal works of van der Merwe, and Matthews and Blakeslee, this change in growth mode is explained in terms of the introduction of strain-relieving misfit dislocations, which appear when the film has reached some critical thickness. Recently it has become clear that this change in growth mode can take place even without the introduction of misfit dislocations. Such dislocation-free coherent islanding, or “roughening,” has been observed experimentally both in Ge/Si and in InGaAs/GaAs systems. Furthermore recent experiments show that in Ge/Si(100) systems, the thin films display a curious asymmetry with respect to the sign of the strain: Films under compression roughen by forming coherent islands while those under tension remain relatively smooth. A possible mechanism behind this strain-induced type of roughening is the subject of this article.


2010 ◽  
Vol 117 ◽  
pp. 55-61
Author(s):  
Masao Kamiko ◽  
Ryoichi Yamamoto

The effects of several surfactants on the homoepitaxial and heteroepitaxial growth of metallic films and multilayers have been studied and compared. Our measurements clearly revealed that pre-deposition of a small amount of surfactant prior to the adatom deposition changed thin film growth mode and structure. The pre-deposited surfactant enhanced layer-by-layer (LBL) growth of the homoepitaxial and heteroepitaxial growth of metallic films. The surfactant also enhanced the epitaxial growth of metallic multilayer.


2011 ◽  
Vol 1292 ◽  
Author(s):  
Nobuyuki Iwata ◽  
Mark Huijben ◽  
Guus Rijnders ◽  
Hiroshi Yamamoto ◽  
Dave H. A. Blank

ABSTRACTThe CaFeOX(CFO) and LaFeO3(LFO) thin films as well as superlattices were fabricated on SrTiO3(100) substrates by pulsed laser deposition (PLD) method. The tetragonal LFO film grew with layer-by-layer growth mode until approximately 40 layers. In the case of CFO, initial three layers showed layer-by-layer growth, and afterward the growth mode was transferred to two layers-by-two layers (TLTL) growth mode. The RHEED oscillation was observed until the end of the growth, approximately 50nm. Orthorhombic twin CaFeO2.5 (CFO2.5) structure was obtained. However, it is expected that the initial three CFO layers are CaFeO3 (CFO3) with the valence of Fe4+. The CFO and LFO superlattice showed a step-terraces surface, and the superlattice satellite peaks in a 2θ-θ and reciprocal space mapping (RSM) x-ray diffraction (XRD) measurements, indicating that the clear interfaces were fabricated.


2011 ◽  
Vol 492 ◽  
pp. 160-163
Author(s):  
Cai Xia Li ◽  
Qing Lv ◽  
Jie Song ◽  
Dan Yu Jiang ◽  
Qiang Li

Nano-sheets are two-dimensional sheet materials exfoliated from the inorganic layered compounds by various physical and chemical methods. Their unique characteristics insertion reaction and excellent physical and chemical properties have attracted more and more researchers' widespread interests. Selecting quartz glass as the substrate, using layer by layer self-assembly technology, different nano-films materials are prepared. UV/Vis spectroscopy confirmed nano-films materials have been successfully assembled using LBL self-assembly technique. Raman spectrum are mainly used to analyze and characterize the structure of nano-films materials.


2014 ◽  
Vol 93 ◽  
pp. 82-89 ◽  
Author(s):  
Aryan Azad ◽  
Eul Noh ◽  
Kang Seop Yun ◽  
Hee June Jeong ◽  
Sang Chul Jung ◽  
...  

Hydrogen has unique physical and chemical properties which present benefits and challenges to its successful widespread adoption as a fuel. The photoelectrochemical (PEC) water splitting process with semiconductor metal oxides can be a promising solution to the global energy problem. Although amongst metal oxides Fe2O3 by 2.2 eV bang gap energy is more applicable, for reducing the recombination of electron and hole, Fe was doped into TiO2. In this study Fe2O3/Fe doped TiO2 photocatalysts were compared with Fe-doped TiO2 and TiO2 structures by using layer by layer-self-assemble (LBL-SA) method and dipping process on FTO glass. According to our results the Fe2O3 coated on Fe doped TiO2 /FTO has had best results.


2011 ◽  
Vol 29 (No. 6) ◽  
pp. 616-623 ◽  
Author(s):  
A.-J. Zhang ◽  
Q.-L. Qin ◽  
H. Zhang ◽  
H.-T. Wang ◽  
X. Li ◽  
...  

The preparation and characterisation of food-grade chitosan from housefly larvae are reported. A refinement procedure was developed to remove larval mouth hooks from the primary chitosan product, which greatly improved the quality of the final product and simplified the production procedures. Different factors affecting chitosan preparation were studied and an orthogonal experiment was designed to determine optimal preparation conditions. When prepared under optimal reaction conditions, the end product was snow-white in colour, had a high deacetylation percentage, good viscosity, and a low ash content. The end product was characterised by Fourier transform infrared spectral analysis, X-ray diffraction analysis, thermo-gravimetric analysis, and differential scanning calorimetry. Its physical and chemical properties and sanitary index were determined and compared to the relevant Chinese standards. The results show that the chitosan we produced under optimal conditions meets the Chinese Fishery Trade Standard SC/T3403-2004 for food-grade chitosan.


1997 ◽  
Vol 11 (21n22) ◽  
pp. 981-987
Author(s):  
H. Q. Yin ◽  
T. Arakawa ◽  
Y. Kaneda ◽  
T. Yoshikawa ◽  
N. Haneji ◽  
...  

La 2-x Sr x CuO 4 ultra-thin films with thickness 200 Å were fabricated by pulsed laser deposition method in oxygen ( O 2) atmosphere. The morphology of deposited films was investigated by reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM) and scanning electronic microscopy (SEM). The strong oxygen ambient pressure dependence of film morphology was observed. In high oxygen ambient pressure, the film growth is dominated by island growth mode. The results imply that the experimental conditions of oxygen ambient pressure and substrate temperature are critical for the layer-by-layer growth mode.


2015 ◽  
Vol 69 (1) ◽  
Author(s):  
Jaroslav Filip ◽  
Peter Kasák ◽  
Jan Tkac

AbstractEarly diagnosis of diseases with minimal cost and time-consumption has become achievable due to recent advances in the development of biosensors. These devices use biorecognition elements for the selective interaction with an analyte and the signal read-out is obtained via different types of transducers. The operational characteristics of biosensors have been reported as improving substantially when a diverse range of nanomaterials is employed. This review presents the construction of electrochemical biosensors based on graphene, atomically thin 2D carbon crystals, a nanomaterial currently the subject of intensive studies. Here, the most attractive directions for graphene applications in biosensor preparation are discussed, including novel detection and amplification schemes exploiting graphene’s unique electrochemical, physical and chemical properties. There is probably a very bright future for graphene-based biosensors, but much further work is required to fulfill the high expectations.


2014 ◽  
Vol 605 ◽  
pp. 665-668
Author(s):  
Saci Messaadi ◽  
Mosbah Daamouche ◽  
Hadria Medouer

Due to their soft operational capacity and magnetic properties, Iron Nickel alloys are of great commercial interest. A simple and inexpensive technique for the production of Nickel-Iron thin films is electrodeposition. A lot of physical and chemical parameters (substrates, concentration, current density, potential, temperature, pH, agents of addition......) can significantly influence the physical properties, such as homogeneity, bright, structure and morphology of the Ni-Fe deposits. This paper presents a study into some characteristics of Ni-Fe deposits on Copper substrates. All the electrochemical experiments were performed in a three electrode cell in which the volume of the bath was 150ml. Electrodeposition of Ni-Fe was carried out potensiostatically from a Brenner type electrolytic bath in [0.1 aqueous solutions of Ni-Fe. The applied potential is-1.20V and the deposition time varies from 10 min to 30 min for all experiments.


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