Effects of Metal-Organic Chemical Vapour Deposition grown seed layer on the fabrication of well aligned ZnO nanorods by Chemical Bath Deposition

Well aligned, long and uniform ZnO nanorods have been reproducibly fabricated adopting a two-steps Metal-Organic Chemical Vapour Deposition (MOCVD) and Chemical Bath Deposition (CBD) fabrication approaches. Thin (<100 nm) ZnO buffer layers have been seeded on silicon substrates by MOCVD and ZnO layers have been subsequently grown, in form of well textured nanorods, using CBD. It has been found that the structure and thickness of the seed layer strongly influence the final morphology and the crystal texturing of ZnO nanorods as well as the CBD growth rate. There is, in addition, a strong correlation between morphologies of CBD grown ZnO nanorods and those of the seed layer underneath. Thus, nanorods deposited over low temperature MOCVD buffer layers are less homogeneous in lateral dimensions and poorly vertically oriented. On the contrary, higher temperature nano-dimensional ZnO seeds favour the CBD growth of almost mono-dimensional homologue nanorods, with an adequate control of the lateral transport of matter. The nanorod aspect ratio values decrease upon increasing the deposition temperatures of the seed layers. Moreover, the nanorods length can be tailored either by adjusting the CBD growth time or by changing concentration of the N,N,N',N'-tetramethylethylenediamine ligand used in the CBD process. In particular, at high concentrations, the CBD process is faster with a greater global aspect ratio in agreement with a preferential one-dimensional growth of the ZnO nanostructures. Finally, these ZnO nanorod arrays possess good optical quality in accordance to the photoluminescence properties

ZnO nanorod arrays fabrication via chemical bath deposition: Ligand concentration effect study

A new ligand, N, N, N', N'-tetramethylethylenediamine, has been used to grow ZnO nanorods on silicon substrates via a two steps approach. A preliminary seeding on silicon substrates has been combined with chemical bath deposition using a Zinc acetate - N, N, N', N'-tetramethylethylenediamine aqueous solution. The used diamino ligand has been selected as Zn(2+) complexing agent and the related hydrolysis generates the reacting ions (Zn(2-) and OH(-)) responsible for the ZnO growth. The seed layer has been annealed at low temperature (<200 degrees C) and the ZnO nanorods have been grown on this ZnO amorphous layer. There is experimental evidence that the ligand concentration (ranging from 5 to 50 mM) strongly affects the alignment of ZnO nanorods on the substrate, their lateral dimension and the related surface density. Length and diameter of ZnO nanorods increase upon increasing the ligand concentration, while the nanorod density decreases. Even more important, it has been demonstrated, as proof of concept, that chemical bath deposition can be usefully combined with colloidal lithography for selective ZnO nanorod deposition Thus, by patterning the ZnO seeded substrate with polystyrene microsphere colloidal lithography, regular Si hole arrays, spatially defined by hexagonal ZnO nanorods, have been successfully obtained. (C) 2010 Elsevier Ltd. All rights reserved

Using dictionaries in teaching English as a foreign language

© 2016 Aleeva and Safiullina.The article discusses the problem of mastering new vocabulary at the English language classes. The brief review of the bilingual English-Russian printed and electronic Dictionaries used at the practical classes of English for the students of the first and second courses of the Germanic Philology Department of Kazan Federal University. The method of compiling thematic dictionaries, its approbation and results are presented

Spectroscopic and Theoretical Study of the Grafting Modes of Phosphonic Acids on ZnO Nanorods

Metal oxides are versatile substrates for the design of a wide range of SAM-based organic-inorganic materials among which ZnO nanostructures modified with phosphonic SAM are promising semiconducting systems for applications in technological fields such as biosensing, photonics, and field-effect transistors (FET). Despite previous studies reported on various successful grafting approaches, issues regarding preferred anchoring modes of phosphonic acids and the role of a second reactive group (i.e., a carboxylic group) are still a matter of controversial interpretations. This paper reports on an experimental and theoretical study on the functionalization of ZnO nanorods with monofunctional alkylphosphonic and bifunctional carboxyalkylphosphonic acids. X-ray photoelectron and infrared spectroscopies have been combined with DFT modeling to explain and understand the interactions that drive the surface anchoring of phosphonic acids on ZnO surface. It was found that both monofunctional and bifunctional acids anchor on ZnO through a multidentate bonding which involves both P=O and P-O moieties of the phosphonic group. Moreover, anchored bifunctional acids bend to the surface, promoting a further interaction between surface hydroxyl groups and carboxylic terminations. This secondary interaction can be limited by increasing the surface density of the anchored molecules

Colloidal lithography and Metal-Organic Chemical Vapor Deposition process integration to fabricate ZnO nanohole arrays

A complete set up of optimal process conditions for an effective colloidal lithography/catalyst assisted MOCVD process integration is presented. It mainly focuses on the determination of the deposition temperature threshold for ZnO Metal-Organic Chemical Vapour Deposition (MOCVD) as well as the concentration of metal-organic silver (Ag) catalyst. Indeed, the optimization of such process parameters allows to tailor the ZnO film morphology in order to make the colloidal lithography/catalyst assisted MOCVD approach a valuable bottom up method to fabricate bi-dimensional ordered ZnO nanohole arrays. (C) 2010 Elsevier B.V. All rights reserved

The ways of expressing objective modality

The article is dedicated to the comparative analysis of expressing the category of modality in the English and Tatar languages and choosing the most suitable ways of rendering its different connotations when translating the Tatar fairy-tale by G.Tukay 'Shuraleh' into English. The author defines the peculiarities of expressing the category of modality in the English and Tatar languages as well as the devices of rendering elements of the category of modality when translating the text from Tatar into English. The sources of the language material for study were the texts of the Tatar fairy-tale by G. Tukay 'Shuraleh' in Tatar and its translation into English done by Ravil Bukharaev

Teaching EFL in multilingual audience of the republic of tatarstan: Philological and methodological approaches

In article authors pay attention to a regional component teaching situation in the Russian educational system in the XXI century on the example of the English speech practice classes for the students of foreign philology department who are trained in "English and Literature", their native language being Tatar. Growth of national consciousness, accentuation of national culture and originality have served as the emergence reason in a practical language course of the regional components higher school with accurately expressed regional content. Implementation of linguistic rates regional component is provided with both philological, and pedagogical methods. In most cases, effective studying of a subject in the field of linguistics requires serial equal pro rata application of classic and innovative methods. Use of the following philological methods when training English in Tatar-speaking audience is recommended: comparisons, contextology, linguistic analysis of the art text, contrast analysis; training methods: Explanatory and illustration, research, method of data problem statement. These methods have been successfully applied on the second year in groups 10.1.-412/411 within project development of English teaching in the Republic of Tatarstan, relying on the following sub-Themes: Greetings, City, Sightseeing, Meals, Theater. During creating presentation such components of language training as work on a pronunciation, translation, creating text have been mentioned. Further use of these methods in case of creating more complex texts about the Republic of Tatarstan and implementation of the gained knowledge in the course of communication in a foreign language is possible

Printing zno inks: From principles to devices

Solution-based printing approaches permit digital designs to be converted into physical objects by depositing materials in a layer-by-layer additive fashion from microscale to nanoscale resolution. The extraordinary adaptability of this technology to different inks and substrates has received substantial interest in the recent literature. In such a context, this review specifically focuses on the realization of inks for the deposition of ZnO, a well-known wide bandgap semiconductor inorganic material showing an impressive number of applications in electronic, optoelectronic, and piezoelectric devices. Herein, we present an updated review of the latest advancements on the ink formulations and printing techniques for ZnO-based nanocrystalline inks, as well as of the major applications which have been demonstrated. The most relevant ink-processing conditions so far explored will be correlated with the resulting film morphologies, showing the possibility to tune the ZnO ink composition to achieve facile, versatile, and scalable fabrication of devices of different natures

Amperometric Biosensor and Front-End Electronics for Remote Glucose Monitoring by Crosslinked PEDOT-Glucose Oxidase

Focusing on the interplay between interface chemistry, electrochemistry, and integrated electronics, we show a novel low-cost and flexible biosensing platform for continuous glucose monitoring. The amperometric biosensing system features a planar three-electrode structure on a plastic substrate, and a wireless near-field communication-powered electronic system performing sensor analog front-end, A/D conversion, digital control, and display tasks. The working electrode is made of electropolymerized poly (3,4-ethylenedioxythiophene) film onto a polyethylene terephthalate/gold electrode followed by immobilization of cross-linked glucose oxidase by glutaraldehyde. The advantages offered by such a device, including low-cost materials and instrumentation as well as the good sensitivity of 9.24 \mu \text{A}/({\mathrm {mM}} \cdot {\mathrm {cm}}^{2}) are promising tools for point-of-care monitoring. It is demonstrated that the devices are good candidates for the development of advanced sensing approaches based on the investigation of the noise produced during operation (fluctuation-enhanced sensing).Luig