Now showing 1 - 6 of 6
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    Ion beam studies on reactive DC sputtered manganese doped indium tin oxide thin films
    (01-04-2008)
    Sarath Kumar, S. R.
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    Malar, P.
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    Osipowicz, Thomas
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    Banerjee, S. S.
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    Indium based transparent conducting oxides doped with magnetic elements have been studied intensively in recent years with a view to develop novel ferromagnetic semiconductors for spin-based electronics. In the present work, we have grown manganese doped indium tin oxide (Mn:ITO) thin films, onto Si and Si/SiO2 substrates by DC reactive sputtering of a composite target containing indium-tin alloy and manganese, in a gas mixture of oxygen and argon. Glancing angle X-ray diffraction (GXRD) studies reveal the polycrystalline nature of the films. Magnetic measurements carried out using vibrating sample magnetometer (VSM) suggest that the films are ferromagnetic at room temperature, with a saturation magnetization of ∼22.8 emu/cm3. The atomic percentages of In, Sn, Mn and O, as estimated using Rutherford backscattering spectrometry (RBS) are 37.0, 4.0, 1.6 and 57.4, respectively. RBS measurements reveal that the interface of the films with Si substrate has a ∼30 nm thick intermediate layer. This layer consists of oxygen, silicon, indium, tin and manganese, in the ratio 1:0.56:0.21:0.07:0.03, indicative of diffusion of elements across the interface. The films on Si/SiO2, on the other hand, have a sharp interface. © 2007 Elsevier B.V. All rights reserved.
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    A comparative study of CuInSe2 and CuIn3Se 5 films using transmission electron microscopy, optical absorption and Rutherford backscattering spectrometry
    (15-08-2005)
    Malar, P.
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    CuInSe2 and CuIn3Se5 films were grown by stepwise flash evaporation onto glass and Si substrates held at different temperatures. Transmission electron microscopy (TEM) studies revealed that the films grown above 370 K were polycrystalline, with CuInSe2 films exhibiting larger average grain size than CuIn3Se5. Optical absorption studies yielded band gaps of 0.97±0.02 and 1.26±0.02 eV for CuInSe2 and CuIn3Se5, respectively. Rutherford backscattering spectrometry (RBS) study of the films on Si showed that CuInSe2/Si structures included an inhomogeneous interface region consisting of Cu and Si, whereas CuIn3Se 5/Si structures presented sharp interface. © 2004 Elsevier B.V. All rights reserved.
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    Transmission electron microscopy and Rutherford backscattering spectrometry studies of Ag2Te films formed from Ag-Te thin film couples
    (01-01-2006)
    Mohanty, B. C.
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    Formation of Ag2Te thin films from room temperature (300 K) solid state reaction of Ag and Te thin film couples is investigated. Rutherford Backscattering Spectrometry (RBS) studies confirmed the complete miscibility of the couples and the stoichiometry of the resulting Ag2Te. Structural analysis by Transmission Electron Microscopy (TEM) showed a fine-grained structure with monoclinic and orthorhombic phases. Annealing at high temperatures resulted in the growth of giant crystallites with monoclinic phase at random sites. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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    Growth and SIMS study of d.c.-sputtered indium oxide films on silicon
    (01-03-2005)
    Malar, P.
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    Mohanty, Bhaskar Chandra
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    Balamurugan, A. K.
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    Rajagopalan, S.
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    Tyagi, A. K.
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    Indium oxide thin films were grown onto Si and quartz substrates by d.c. reactive sputtering of elemental indium. X-ray diffraction and transmission electron microscopy studies confirmed the single-phase and polycrystalline nature of the films. Secondary ion mass spectrometry investigations of In 2O3/Si structures showed the formation of an inhomogeneous interface region ̃20 nm thick between In2O3 and Si. The overall feature of the interface remained the same under annealing in an oxygen atmosphere, but annealing in an argon atmosphere drastically altered the nature of the interface. The observations indicate that interface formation and stability depend critically on the availability of oxygen. Copyright © 2005 John Wiley & Sons, Ltd.
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    Characterization of stepwise flash-evaporated CuInSe2 films
    (28-06-2004)
    Malar, P.
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    Das, V. Damodara
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    CuInSe2 (CIS) films were deposited by stepwise flash evaporation from polycrystalline powder source onto glass substrates held at various temperatures ranging from 100 to 560K. The phase purity and microstructure were analyzed by transmission electron microscopy. The investigations show that films grown at 300K and below were amorphous, whereas those grown at 370K and above were polycrystalline in nature. The grain size in polycrystalline films were found to improve with increase in substrate temperature and during post-deposition annealing. The films had near stoichiometric composition as revealed by Rutherford backscattering spectrometry. Analysis of the optical transmittance spectra of CIS films deposited at 520K yielded a value of ∼0.97eV for the fundamental band gap. © 2004 Elsevier Ltd. All rights reserved.
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    Growth and characterization of stepwise flash evaporated CuInTe2 thin films
    (01-02-2009)
    Ananthan, M. R.
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    CuInTe2 films grown by stepwise flash evaporation onto glass and silicon substrates held at 573 K were studied using X-ray diffraction (XRD), transmission electron microscopy (TEM), Rutherford backscattering spectrometry (RBS) and Raman spectroscopy. XRD and TEM studies showed the formation of single-phase polycrystalline CuInTe2. Results of the RBS measurements showed the films to be near-stoichiometric and negligible diffusion of elements across the CuInTe2/Si interface. Various lattice vibrational modes identified by Raman measurements were found to match well with those reported for single-crystal CuInTe2, confirming the crystalline quality of the CuInTe2 thin films. © 2008 Elsevier B.V. All rights reserved.