• Composition dependence of density of states in a-Se$_{100−x}$Sn$_{x}$ thin films

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    • Keywords


      Chalcogenide glasses; localised states; space charge limited conduction; high field conduction.

    • Abstract


      The present paper reports the DC conductivity measurements at high electric fields in vacuum evaporated amorphous thin films of a-Se$_{100−x}$Sn$_{x}$ ($x = 0, 2, 4, 6$) glassy alloys. Current–voltage ($I–V$) characteristics have been measured at various fixed temperatures. In these samples, at low electric fields, ohmic behaviour is observed. However, at high electric fields ($E \sim 10^{4}$ V/cm), non-ohmic behaviour is observed. An analysis of the experimental data confirms the presence of space charge limited conduction (SCLC) in the glassy materials studied in the present case. From the fitting of the data to the theory of SCLC, the density of defect states (DOS) near Fermi level is calculated. Increase in DOS with increase in Sn concentration has been found which could be correlated with the electronegativity difference between the two elements used here in making the glassy alloys. The peculiar role of the element Sn as an impurity in the pure Se glassy alloy is also discussed.

    • Author Affiliations


      N Sharma1 S P Singh1 S Kumar1

      1. Department of Physics, Christ Church College, Kanpur 208 001, India
    • Dates

  • Pramana – Journal of Physics | News

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      Posted on July 25, 2019

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