Single Crystal Whiskers

The reactants were ultrasonically dispersed in ethylendiamine, then transferred to a Teflon-lined autoclave and gradually heated up to 160°C. The products were filtered out, washed with absolute alcohol, normal HC1 solution and water and finally dried in vacuum. In the product nano-fibres and near single-crystal whiskers were obtained. 

Key words Bi2Sr2CaCu208+x c-axis Transport and Magneto-transport, Single Crystal Whiskers, d-wave, Order Parameter Symmetry, Josephson Flux-flow Resistivity. 

Grade Polycrystalline form in high-purity electronic grade, single crystals, whiskers. 

One should emphasize that the adsorption-active medium itself does not create any defects within an object it may only facilitate their development. For this reason some thread-like defect-free single crystals (whiskers) may be insensitive to the action of the medium. 

Aluminum nitride was synthesized from ammonia using the gas-transport reaction method. This yielded single-crystal "whiskers" about 1-2 mm long and a few tenths of a millimeter in diameter. The x-ray diffraction study was carried out on transparent single crystals (whiskers)... 

Other forms ofvery fine oxide fibers exist or are being developed. Single crystal whiskers which pose health risks and also present difficulties for handling, because of their very small dimensions, have not found wide use. Nano-oxide fibers are being developed which may be fine enough for liquid crystal technology to be used so as to handle them but as yet remain a possibility for the future. 

Inorganic materials such as chalk, flour, china, clay, mica, barytes. Fuller s earth, Aerosil (finely divided Si02), asbestos, glass-fiber, and metal or oxide single crystals (whiskers) are all used as fillers. Organic fillers include wood flour, cellulose flakes, foam-rubber chips, paper cuttings. 

Metal particle catalyzed chemical vapor deposition is the most versatile VLS process (Table II) yielding a wide range of single crystal whiskers and nanowhiskers [1-2] [5-6], short amorphous or polycrystalline fibers [1] [7], and nanotubes [8]. Laser ablation of selected metal alloys is a recent VLS process used for the synthesis of semiconductor nanowire [74]. Metal particle catalyzed carbothermal reduction, another VLS process, yields single crystal whiskers [9-10]. Metal catalyzed arc discharge [11], metal particle catalyzed laser ablation [12], and metal particle catalyzed plasma arc discharge [13] yield nanotubes by a VLS mechanism. 

Figure 2. Single crystal whisker tip consisting of a solidified gold catalyst droplet. Courtesy of Dr. E. I. Givargizov, Russian Academy of Sciences, Moscow...

Amorphous and polycrystalline fibers and near-single crystal whiskers were obtained having diameters of 10-150 nanometers and lengths of several micrometers. Growth of whiskers and short fibers by this method is believed to proceed by a solution-liquid-solid (SLS) phase transformation, suggesting that similar synthesis routes may now also become available for other covalent short fibers and perhaps whiskers. 

The fate of metal catalyst particles during the growth of nanotubes parallels that observed for the metal catalyst particles during the growth of single crystal whiskers. This commonalty suggests that vapor-liquid-solid phase transformations are involved in the majority of cases. 

J. V. Milewski, Method and apparatus for continuous growth of single crystal whiskers, US Patent 5,404,836, April 11,1995. 

Single crystal whiskers Amorphous fibers Single crystal fibers Amorphous fibers... 

Types of the investigated samples Single crystal Overdoped single crystal Whisker Thin film... 

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