Papers by Hulya Demiryont
Thin Solid Films, Mar 1, 1983
A new preparation technique called "reactive evaporation" is discussed with reference to the prod... more A new preparation technique called "reactive evaporation" is discussed with reference to the production of AI-AIOx and Sn-SnOx cermet films. Sample properties characterized by the metallic particle concentration within the cermet films were found to depend on the deposition rate, the pressure and the species of residual gas during deposition, the source-substrate distance and the substrate temperature. A1-A1Ox cermets exhibit three distinct types of current-voltage characteristic, which can be related to the particle concentration. Ohmic conductivity, switching and memory effect properties and non-linear current-voltage characteristics were observed with A1-AIOx cermet films independently of the electrode material (aluminium, gold) and the sample thickness (100-1000,~) when the aluminium particle concentration was decreased. Some general properties of Sn-SnO x cermet films were studied in relation to the preparation conditions. Microstructure examination by transmission electron microscopy, resistance measurements on SnO~ films prepared in strip and sandwich form and optical transmissivity studies were carried out as functions of time. The effects of moderate heat treatment on the sample properties were also examined. 16 19 of metal and oxide from separate sources, and reactive sputtering-, but no work has been carried out on reactive evaporation.
Applied optics, Sep 1, 1991
Transparent and optical-grade TiO 2 coatings were prepared by sol-gel spinning and ion-beam sputt... more Transparent and optical-grade TiO 2 coatings were prepared by sol-gel spinning and ion-beam sputtering techniques. We investigate process parameters for the fabrication of sol-gel spin-coated TiO 2 films exhibiting high optical quality comparable with that of ion-beam-sputtered TiO 2 films. X-ray diffraction studies showed the sol-gel-deposited films to be amorphous for heat treatments below 350°C, whereas the ion-beamsputtered films were slightly crystalline and exhibited the anatase structure. The refractive index and the extinction coefficient were evaluated from transmittance characteristics in the ultraviolet, visible, and nearinfrared regions. Transmission spectra and ellipsometric measurements showed that spin-coated films were essentially optically equivalent to those prepared by ion-beam sputter deposition.
Applied optics, Jan 10, 1992
A new quasi-symmetric electrochromic device is described for transmission modulation of a switcha... more A new quasi-symmetric electrochromic device is described for transmission modulation of a switchable window. The calculation technique to design such an electrochromic window for transmission (or reflection) modulation is applied to the (electrode/WO,/electrolyte/WOs/electrode) system. Advantages and limits of such a quasi-symmetrical system are also discussed.
ASTM International eBooks, Dec 4, 2008
Solar Energy Materials, Sep 1, 1989
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ASTM International eBooks, Feb 12, 2009
Proceedings of SPIE, Nov 13, 2001
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SAE technical paper series, Feb 1, 1991
Journal of The Optical Society of America A-optics Image Science and Vision, 1984
Proceedings of SPIE, Dec 12, 1989
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Proceedings of SPIE, Nov 12, 1987
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Journal of vacuum science & technology, May 1, 1985
Applied optics, Apr 15, 1989
Tungsten oxide films (W0 3) are deposited by thermal evaporation techniques using the starting ma... more Tungsten oxide films (W0 3) are deposited by thermal evaporation techniques using the starting materials of tungsten (W) and tungsten oxide (W0 3). By varying deposition parameters, three main types of W03 film exhibiting different optical properties form. These are blue, gray, and colorless films. The samples are characterized optically and morphologically. Blue-colored samples exhibit a broad selective absorption peak around 1000 nm. Absorption of gray-colored samples spreads out in the visible region in an exponential form. The refractive indices of samples are between 1.9 and 2.1. The energy gap of blue and colorless samples is 3.32 eV, but that of the gray-colored samples is 3.18 eV and smaller. X-ray diffraction studies reveal that evaporated W0 3 films are amorphous. Fourier transform infrared spectra of samples were studied to evaluate bond properties. Colorless near-stoichiometric tungsten oxide films exhibit three absorption peaks in the 1000-600-cm-1 window. These peak locations, in terms of cm-' window. These peak locations, in terms of cm-1 , are 669,737, and 813.-20 cm-1 apart. chromism (EC). A tungsten oxide film exhibits reversible coloring (blue) and bleaching (colorless), depending on the electrical field direction applied to the material. The quality of an EC material such as achievable transmittance contrast between colored and colorless states, response time to applied voltage, lifetime of coating, etc. depends on material properties of the W0 3 films. The better EC properties are observed on amorphous, porous, oxygen deficient W0 3 films deposited by e-beam or thermal evaporation techniques. There are various studies on EC properties of W0 3 but not on optical parameters, e.g., refrac
Proceedings of SPIE, Dec 1, 1990
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Applied optics, Sep 15, 1987
Classified abstracts 65574565 upper values (~ I mA cm 2) the columnar structure is not seen and o... more Classified abstracts 65574565 upper values (~ I mA cm 2) the columnar structure is not seen and only phase TiN is detected. These different results may be explained by the role of the discharge current and the control of ion bombardment of the substrate during the film growth process.
Applied optics, Apr 15, 1986
Composition-dependent optical properties of (Al 2 0 3) 1- ,-(AlN), films deposited by the laser-a... more Composition-dependent optical properties of (Al 2 0 3) 1- ,-(AlN), films deposited by the laser-assisted chemical vapor deposition (L-CVD) technique are investigated. Three distinct substrate temperature regions give rise to three distinct film compositions from A1 2 0 3 , through oxynitride composites, and ultimately to AIN. Optical parameters of the films deposited on fused quartz substrates are deduced from spectrophotometric transmittance characteristics in the spectral region ranging from 0.18 to 3.5,um. The optical energy gap of the films is determined from optical absorption spectra. Fourier transfer infrared spectra (4400-400 cm-') are used to characterize the chemical composition of the films.
MRS Proceedings, 1991
Layered electrochromic glass was investigated in order to test the feasibility of using hierarchi... more Layered electrochromic glass was investigated in order to test the feasibility of using hierarchical designs for new electrochromic devices. Matrix-type synthetic electrochromic structures were designed, and two types of matrix devices, polarization and plating, were produced and evaluated. The application and device requirements of electrochromic glasses are discussed.
Annual Meeting Optical Society of America, 1987
Oxides of tungsten are deposited by (a) reactive evaporation of tungsten and (b) thermal evaporat... more Oxides of tungsten are deposited by (a) reactive evaporation of tungsten and (b) thermal evaporation of WO3. Optical properties of as-deposited films are studied. Optical parameter spectra of the films deposited on Corning 7059 glass are deduced from specrtrophotometric transmittance and reflectance characteristics. Bond properties of the WOx films are examined by Fourier transform infrared (FTIR) spectral data.
Applied optics, Aug 15, 1985
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Papers by Hulya Demiryont