Persons

The possibility of the synthesis of carbon nanotubes by the method of chemical deposition of acetylene at 400-800 °C temperature on the surface of a metal film of amorphous alloy Ni-Ta-N with low nickel content (~ 25 at.%) has been demonstrated. It has been shown that an addition of nitrogen into the Ni-Ta alloy promotes the formation of tantalum nitride and extrusion on the surface of the nickel clusters, acting as a catalyst in the growth of carbon nanotubes. The Raman spectroscopy has revealed that while increasing the temperature of the synthesis process the quality of the carbon nanotubes is improved.

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One way to obtain perfect nitride structures for microelectronics is to use the atomic layer epitaxy growth method. The paper considers the influence on the growth dynamics and uniformity of the distribution of the deposited gallium nitride (GaN) layer of such process parameters as the pressure in the reactor, the flow rate of the trimethylgallium precursor and the substrate temperature in the deposition zone (growth temperature). The experiments were carried out in the original reactor in which the flow of gases to the surface of the substrates was carried out horizontally, the growth temperature in different experiments was in the range of 450-540 °C, pressure was varied from 4·10 Pa (400 mbar) up to 5·10 Pa (50 mbar), flow trimethylgallium ranged from 3 to 120 ml/min. The thickness of the layers is determined on a spectral ellipsometer. Obtained samples were studied by atomic-layer microscopy. Conditions of carrying the process for obtaining a uniform thickness of epitaxial layers of GaN on sapphire substrates have been researched.

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It has been shown that using the technology of the melt gettering by aluminum it is possible to reduce the concentration of oxygen, decreasing the efficiency of photoelectric devices. The optically active oxygen content has decreased to 5·10 cm - at the beginning of the monocrystal, to -----at the end with a simultaneous increase in the uniformity of its distribution over the length and cross-section of the ingot. The lifetime of the minority carriers has been more than three times increased. The primary effect of solar degradation efficiency of solar cells has demonstrated less than 2% decrease.

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