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Evaporation Techniques (evaporation + techniques)

Distribution by Scientific Domains

Polymers and Materials Science	50%
Physics and Astronomy	50%

Selected Abstracts

Effect of substrate temperature on the properties of vacuum evaporated indium selenide thin films

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2005
C. Viswanathan
Abstract Thin films of InSe were obtained by thermal evaporation techniques on glass substrates maintained at various temperatures (Tsb = 30°, 400°C). X-ray diffraction analysis showed the occurrence of amorphous to polycrystalline transformation in the films deposited at higher substrate temperature (400°C). The polycrystalline films were found to have a hexagonal lattice. Compositions of these films have been characterized by EDAX and the surface analysis by scanning electron microscopy. Optical properties of the films, investigated by using spectrophotometer transmittance spectra in the wavelength range (300 , 1100 nm), were explained in terms of substrate temperatures. Films formed at room temperature showed an optical band gap (Egopt) 1.56 eV; where as the films formed at 400°C were found to have a Egopt of 1.92 eV. The increase in the value of Egopt with Tsb treatment is interpreted in terms of the density of states model as proposed by Mott and Davis. The analysis of current -Voltage characteristics, based on space charge limited currents (SCLC) measurements, confirms the exponential decrease of density of states from the conduction band edge towards the Fermi level for both the amorphous and polycrystalline films. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Crystalline Organization of a Methanofullerene as Used for Plastic Solar-Cell Applications ,

ADVANCED MATERIALS, Issue 9-10 2004
X. Yang
Crystalline organization of a methanofullerene, [6,6]-phenyl C61 butyric acid methyl ester (PCBM), as achieved in various thin-film deposition techniques, is reported. Mechanically stable, and thus self-supporting, thin films obtained via fast solvent evaporation techniques are found to be composed of densely and homogeneously distributed PCBM nanocrystals with various crystallographic orientations, as shown schematically in the Figure. [source]

Electrodeposition study of ODN:SWCNT hybrids on gold substrates

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2008
Roya R. Lahiji
Abstract Sonication of short single-stranded DNA (oligodeoxyribonucleotide; ODN) with Single-Walled Carbon Nanotubes (SWCNTs) greatly facilitates the dispersion of SWCNTs from entangled ropes in an aqueous solution, creating ODN:SWCNT hybrids. Electrodeposition has been investigated to determine if well-dispersed ODN:SWCNT hybrids on a metal substrate can be created. Preliminary studies indicate that electrodeposition using an Au substrate held at +0.5 V produces ODN:SWCNT hybrids that are uniformly deposited across the Au substrate. This result can be compared to samples produced by drop casting and evaporation techniques which yield a thick tangled mat of ODN:SWCNT hybrids across the substrate. The resulting electrodeposited samples were characterized using Scanning Probe Microscope (SPM) and X-ray Photoemission Spectroscopy (XPS) techniques. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Analyses of Thick Lithium Coatings Deposited by Sputter-Evaporation and Exposed to Air

PLASMA PROCESSES AND POLYMERS, Issue S1 2009
C. Rigaux
Abstract Lithium coatings on various substrates have numerous applications: Boron neutron capture therapy, neutron activation analysis, super-conducting tokamak etc. Traditionally these coatings are produced by well-known techniques such as electrochemistry and evaporation. In this work, we investigated a new method based on sputter-evaporation, which enables thick coatings (>10,µm) to be built on various substrates within a short timeframe. In order to minimize the process time, evaporation techniques can be used but the coating quality suffers. Moreover, it is well known that the use of DC magnetron sputtering results in the deposition of good quality coatings (smoothness, density, adhesion); however, the deposition rate is low. The rationale of this work is to combine these two techniques, yielding a sputter-evaporation process that possesses the advantages of each separate technique. Li is placed in a stainless steel crucible (cathode), and heated by the plasma generated by a magnetron discharge. The Li temperature is measured by a thermocouple welded onto the cathode and measured at different plasma power densities. The deposition rate of lithium is measured using a quartz balance and by profilometry, at several temperatures (from 0 to 580,°C). Li samples were depth-profiled with the resonant nuclear reaction 7Li(p,,)7. In addition to the concentration, certain characteristics like the density and the chemical reactivity of layers, are also important. Thus we have studied the evolution of the density with time, estimated by weight and profilometry measurements, and the change in morphology, by cross-sectional scanning electron microscopy (SEM), of samples exposed to air at room temperature. The evolution of the film compounds have also been determined by X-ray powder diffraction. These physical properties have been investigated for various bias substrates during deposition. [source]