Wyniki wyszukiwania - BazTech

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Catalyst free growth of single-crystalline bismuth nanorods by closed space sublimation technique

Usman W., Maqsood A.

Materials Science Poland

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2015

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Vol. 33, No. 2

381--390

EN

In the present study, bismuth (Bi) thin films having thickness of 335 nm have been deposited onto a glass substrate by closed space sublimation (CSS) technique. Besides this, spontaneous growth of Bi nanorods has also been investigated for the first time, without template and catalyst assistance in a substrate temperature range of 380 to 430 degrees C using CSS technique. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to investigate microstructure, morphology and roughness of the Bi nanorods. The diameter and length ranges of Bi nanorods were 80 to 400 nm and 3 to 5 mu m, respectively. Moreover, they exhibited a rhombohedral structure with a dominant peak indexed at (012), (104), and (110). The mass percentage of Bi, determined by energy dispersive X-ray (EDX), was 99.93 %. The studies of electrical resistivity, Hall coefficient, magnetoresistivity, hole mobility and carrier concentration of Bi thin films were performed at 300 to 350 K and the electrical properties were found to be a function of temperature. The basic aim was to investigate the spectacular evolution of Bi nanostructures on as-deposited thin films and effects of thickness on their structural, electrical and dielectric properties. Detailed examination of SEM micrographs eliminated all other growth modes except self-catalytic tip growth by Vapor-Solid (VS) growth process which is believed to provide the driving force for spontaneous nanorod growth at high substrate temperature. Deposition of thinner Bi films provided a new possibility for fabrication of Bi nanorods of high quality.

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Wpływ parametrów wyładowania jarzeniowego na skuteczność grzania podłoży metalowych w procesach plazmowych

Cłapa M.

Inżynieria Materiałowa

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2010

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Vol. 31, nr 4

917-920

PL

Temperatura podłoża jest jednym z głównych parametrów obróbki powierzchniowej prowadzonej za pomocą plazmy wyładowania jarzeniowego. Dotyczy to zarówno procesów modyfikacji warstwy wierzchniej, jak i osadzania powłok. W pracy przedstawiono wyniki badań skuteczności grzania podłoży metalowych w plazmie wyładowania jarzeniowego. Aby możliwe było porównanie wyników przeprowadzone badania polegały na utrzymaniu stałej temperatury podłoża (300 lub 400°C) przy zmieniających się warunkach wyładowania. Badania prowadzono dla rożnych składów atmosfery w komorze reaktora (Ar, N2, CH4, H2) oraz dla mieszanin tych gazów. Zmieniane było ciśnienie oraz parametry zasilania reaktora. Testy prowadzono dla trzech rodzajów wyładowań (DC, RF, DC-imp). Przedstawione wyniki testów mogą być pomocne przy opracowywaniu technologii obróbki powierzchniowej wykorzystujących techniki plazmowe.

EN

Surface temperature is very important in plasma deposition and surface modification processes. In this paper we present measurements of metal surface heating efficiency in glow discharge plasma. To achieve comparable results we held the substrate temperatures constant at 300 or 400°C while varying other plasma parameters (pressure, gas flow rates and applied power). Three different power supplies (DC, pulsed DC and RF) were used in this study. The measurements were repeated for different working gasses (Ar, N2, CH4 and H2) and for some of their compositions. Our results can be useful for designing plasma assisted surface treatment processes.

3

Counter electrodes for WO/sub 3/-based electrochromic coatings

Żelazowska E., Ziemba B., Lachman W.

Optica Applicata

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2000

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Vol. 30, nr 4

663-670

EN

Thin polycrystalline electrochromic tungsten trioxide as well as nickel, vanadium and titanium oxide films with and without lithium additive were prepared by spray pyrolysis on glass coated with SnO/sub 2/:F, using acetylacetonates as precursor materials. The substrate temperature was held at 600 degrees C for WO/sub 3/ and 680 degrees C for the other metal oxide films. Electrochromic colouration and bleaching characteristics were examined in the transmissive electrochromic cell arrangement, using LiClO/sub 4/-poly(ethylene oxide) polymer electrolyte and significant changes of optical transmission in the visible and solar range, up to 70%, were observed. The obtained films were electrochemically stable and colouration and bleaching cycles were reversible at a voltage of +or-(1-25) V. The start of the electrochemical reactions for most of the films obtained was observed in the range of +or-(0.3-4) V.