Yazar "Atilgan, Ismail" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • [ X ]
    Öğe
    Effects of tail states on the conduction mechanisms in silicon carbide thin films with high carbon content
    (Pergamon-Elsevier Science Ltd, 2011) Sel, Kivanc; Akaoglu, Baris; Atilgan, Ismail; Katircioglu, Bayram
    Hydrogenated amorphous silicon carbide (a-SiCx:H) films of different carbon content (x) were deposited by radio frequency plasma enhanced chemical vapor deposition (PECVD) system. Apart from the X-ray photoelectron spectroscopy (XPS) and UV-Visible transmission analyses, the resistivity measurements between 293 K and 450 K were emphasized to assess the eventual transport mechanisms. The film resistivities are unexpectedly found relatively low, especially for high carbon content. In the frame of exclusive band conduction, the apparent thermal activation energies, evaluated from Arrhenius type plot remain too low compared to half values of the optical gaps. Numerical analyses were undertaken by extending conduction from the band conduction about the mobility edge inside the band gap by including the nearest neighbor hopping (NNH) conduction across the localized tail states. By successfully fitting the formulated conductivity expression to the experimental results, parameters such as tail states distributions, true activation energies to the mobility edge have been retrieved. (C) 2010 Elsevier Ltd. All rights reserved.
  • [ X ]
    Öğe
    Electroluminescence properties of a PIN structure made by nearly stoichiometric a-SiCx:H active layer
    (Pergamon-Elsevier Science Ltd, 2009) Sel, Kivanc; Akaoglu, Baris; Ozdemir, Orhan; Atilgan, Ismail
    a-SiCx:H PIN diode has been fabricated within a single pump-down process under the same deposition conditions used for doped and undoped PECVD grown thin films, whose optical and electrical properties are determined and compared with a-Si:H. Current-voltage characteristics of PIN diode are evaluated and concluded to be limited by tunnelling of holes at p-i interface into valence band tail states. Electroluminescence measurements revealed radiative monomolecular recombinations. Deconvolution of the luminescence spectra is utilized to analyse recombination mechanism to be dominated by the transitions between band tails and deep states, which are created by the large density of both silicon and carbon dangling bonds, probable in the stoichiometric a-SiCx:H film. Finally, a small luminescence peak around 1.9 eV would be an evidence of reduced probability of tail to tail transitions, than that of the transitions between tail and deep states. (C) 2008 Elsevier Ltd. All rights reserved.