Metal oxide Nanostructures from Electrospun Carbon Templates ab 79 € als Taschenbuch: Metal Oxide Nanofibers and Nanotubes. Aus dem Bereich: Bücher, Wissenschaft, Chemie,
Metal oxide Nanostructures from Electrospun Carbon Templates ab 79 EURO Metal Oxide Nanofibers and Nanotubes
Fabrication of physical or bio-/electro-chemical sensors at ultra-small scale, but with novel functionalities and improved performances will reach soon a serious limitation. Nanotechnology may overcome this restriction by providing access to a borderless range of nanostructures with intriguing features and numerous advantages. Nowadays, the true nano- art expresses the ability to easily tailor their physical properties to meet the device requirements. In this work we blended specific top-down patterning methods with adequate bottom-up electrochemical routes using nanoporous alumina templates, owning to a versatile platform for development of localized nanowires with densities and shapes tunable in a large extent. Smartly engineered nanowire-templated micro-strips were used to probe the concept of highly-sensitive capacitive pH detection at nanoscale. This book connects theoretical and practical elements, allowing the reader to gain a general insight into the secrets of nanotechnology and modern devices assembly. Technology-related problems, engineering tips, modeling and electrical investigation protocols coupled with chip integration methodologies were discussed and evaluated.
Self-assembled peptide nanostructures present a vast potential for materials science. These nanostructures are formed by self-assembly of small molecular weight molecules. Programmed assembly of peptides can be achieved by providing certain inputs at the design level. Noncovalent interactions such as electrostatic interactions, hydrogen bonding, pi-pi interactions, solvophobic effects and van der Waals forces can be used as inputs determining fate of a supramolecular ensemble. Supramolecular ensembles can be used as functional templates for the synthesis of hybrid organic-inorganic and purely inorganic nanomaterials. Peptide nanostructures can be utilized in patterning of organic materials as well. For instance, encapsulation of chromophore molecules in peptide nanostructures presents an interesting approach in controlling photophysical properties of enclosed molecules. Peptide nanostructures have shown great versatility and applicability in materials science. This fact is not surprising, because numerous phenomena taking place in nature actively exploit polypeptides as a handy tool in materials synthesis and its hierarchical organization.
III-nitride compound semiconductors (AlN, GaN, InN) and their alloys have emerged as versatile and high-performance materials for a wide range of electronic and optoelectronic device applications. Although high quality III-nitride thin films can be grown at high temperatures (1000 °C) with significant rates, deposition of these films on temperature-sensitive device layers and substrates necessitates the adaptation of low-temperature methods such as atomic layer deposition (ALD). When compared to other low-temperature thin film deposition techniques, ALD stands out with its self-limiting growth mechanism, which enables the deposition of highly uniform and conformal thin films with sub-angstrom thickness control. These unique characteristics make ALD a powerful method especially for depositing films on nanostructured templates, as well as preparing alloy thin films with well-defined compositions. This monograph reports on the development of low-temperature ( 200 °C) plasma-assisted ALD processes for III-nitrides, and presents detailed characterization results for the deposited thin films and fabricated nanostructures.
Nanoporous Anodic Alumina has received significant attention of the world researchers as a template for the low cost fabrication of nanostructures of metals, semiconductors, polymers, superconductors, etc. In the present work it has been demonstrated that the type of electropolishing pre-treatment and the resulting nano-features on aluminum surface can influence the hexagonal ordering of the pores developed during anodizing. Apart from improving the ordering quality the work has been extended to relate the photoluminescence with the ordering quality of anodic alumina, prepared at a given anodizing voltage. New templates have been prepared, based on sandwiched structures. The two layers for the sandwiched structures were prepared by complete anodization of aluminum sheet from opposite sides and by changing the anodizing conditions, forming a new superlattice. Employing anodic alumina as a template, elctrodeposition of nickel nanowires in aqueous medium and in Dimethyl sulfoxide (DMSO) has been demosntrated. Silver nanowires have also been grown in the template with electrochemical (AC) and electroless deposition techniques.
Cadmium Sulfide (CdS) nanostructures are attractive for applications in semiconductor lasers, light emitting diodes, photovoltaic cells and display devices. The present report is concerned with the growth and characteristics of CdS nanostructures for possible applications in charge storage, nano-capacitor, photovoltaic and photosensing devices. The fabrication of hexagonal, well-arranged porous alumina templates and the growth of CdS nanowires in the templates are discussed. The characteristics of needle- and wire-like CdS nanocomposites grown in a polymer matrix are analyzed. The nanocomposite/conducting polymer device exhibits negative resistance and charge storage characteristics. MWCNT-CdS nanostructures embedded in a conducting polymer shows a broad spectral response (400-1000nm), which is attractive for hybrid photovoltaic devices. The growth of core-shell Ge/CdS radial nanowire heterostructures by a combination of vapor-liquid-solid growth and chemical process is reported. The photodiode behavior of Ge/CdS heterojunction and enhancement of photocurrent with a broadband response from visible to near-IR due to the formation radial heterojunctions are discussed in details.
Magnetic nanostructures have attracted increasing attention because of their potential applications in high-density data storage and in sensor technology. An understanding of the fundamental physical properties of these nanostructures is of interest in the study of atomic structures and micromagnetism. This book presents a study on the growth of nickel nanowires in commercially available templates. Electrodeposition was used through the pores of a template to produce nanowire matrices. Dependence of the nanowire growth rate, quality of deposit, growth uniformity, crystal orientations and other physical properties of the nanowire network were studied using various process parameters. Structural properties of the nanowire were characterised using AFM, SEM, EDX and TEM. Magnetic properties of the nanowires were studied using a VSM and MFM. Using OOMMF software magnetic behaviour of the nanowires was simulated and compared with the experimental coercivity values and magnetisation behaviour. The target audience of this book is the postgraduate students and the researchers who would like to study the fabrication and characterisation of magnetic nanowires.
One-dimensional nanostructures are of great interest because of their potential application in many areas, such as high-density perpendicular magnetic recording media and nanosensors. The synthesis and precise control of such a magnetic nanostructure on a large scale is a challenging issue in material science. One strategy is to electrode posit magnetic nanowires into nanochannels of porous anodic aluminum oxide (AAO) templates. In this work we focused on Fe-nanowire arrays with diameters of about 30 nm, using the shape anisotropy and the crystalline anisotropy. In the present paper, we report a unique dynamically controlled growth method to prepare Fe nanowire with preferred (110) orientation along the wire. The effects of pH, symmetry/asymmetry electrodeposition voltage and frequency on magnetic properties of nenowires were investigated. Computing the samples magnetization proved that by increasing the non symmetric voltage, magnetization of nanowires increased. On the other hand, the values of coercive field and squareness of samples showed that 1000 Hz is the optimum system frequency which reveals special properties of Fe nanowires discussed in this book.