Simple Band Model for Amorphous Semiconductor Alloys

  • Morrel H. Cohen
  • H. Fritzsche
  • S. R. Ovshinsky
Part of the Institute for Amorphous Studies Series book series (IASS)


Amorphous covalent alloys particularly of group-IV, -V, and -VI elements are readily formed over broad ranges of composition.1–6 They have been described as low-mobility electronic intrinsic semiconductors with a temperature-activated electrical conductivity σ = σ 0×exp(-ΔE/kT) which sometimes extends well into the molten state.2,3,7 They remain intrinsic with changed ΔE when their composition is changed.1,5,7 These alloys transmit infrared light up to an exponential absorption edge from which an energy gap E g is estimated.1,2 The value of E g usually is smaller than 2ΔE, often by as much as 10–20%.7,8 Photoconductivity9 and recombination-radiation10 measurements have been interpreted as giving evidence for the presence of localized states in the gap.


Band Model Mobility Edge Excess Conductivity Soviet Phys Localize Positive Charge 
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Copyright information

© Plenum Press, New York 1991

Authors and Affiliations

  • Morrel H. Cohen
    • 1
  • H. Fritzsche
    • 1
  • S. R. Ovshinsky
    • 2
  1. 1.James Franck Institute and Department of PhysicsUniversity of ChicagoChicagoUSA
  2. 2.Energy Conversion Devices, Inc.TroyUSA

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