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Journal of Materials Science

, Volume 42, Issue 8, pp 2712–2716 | Cite as

Study of defect states in a-Se85Te15−xPbx thin films by space charge limited conduction mechanism

  • V. S. Kushwaha
  • A. KumarEmail author
Article

Abstract

Current–Voltage (IV) characteristics have been studied at various temperatures in vacuum evaporated thin films of a-Se85Te15−xPbx (x = 0, 2, 4, 6) alloys. These characteristics show that, at low electric fields, an ohmic behaviour is observed. However, at high electric fields (E ∼ 104 V/cm), the current becomes superohmic. At high fields, in case of samples having 0 and 2 at% of Pb, the experimental data fits well with the theory of space charge limited conduction (SCLC) in case of uniform distribution of localized states in the mobility gap. Such type of behaviour is not observed at higher concentration of Pb in the present glassy system due to high conductivity. In these samples, joule heating due to large currents may prohibit the measurement of SCLC. Using the theory of SCLC for the uniform distribution of the traps, the density of localized defect states near Fermi level is calculated for these compositions. The results indicate that the density of defect states near Fermi level increases on addition of Pb to binary Se85Te15alloy. This is explained in terms of electronegativity of Pb as compared to host elements.

Keywords

Joule Heating Defect State Chalcogenide Glass Glassy Alloy Ohmic Behaviour 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media, LLC 2006

Authors and Affiliations

  1. 1.Department of PhysicsHarcourt Butler Technological InstituteKanpurIndia

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