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Semi- and photo-conductive thin films of polyacrylonitrile with the thickness of a few microns of less are prepared by the silent electric discharge in acrylonitrile monomer vapor followed by the heat-treatment at temperatures of 150°C to 500°C. The growth rate of the films deposited under the discharge is proportional to the monomer vapor pressure and the discharge voltage. The electrical resistivity and its activation energy decrease and the spectral responses of both the photocurrent and the optical absorption shift toward longer wavelength as the heat-treatment temperature rises. Non-ohmic characteristics of the electrical conduction are observed in the filed higher than ∼3×104 V/cm, and agree with the theoretical expression of the modified Pool-Frenkel effect. The energy depth of the trap estimated from the thermally stimulated current measurement is ∼0.5 eV.

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Dark-spot defects (DSD) in a GaAs-Ga1−xAlxAs double-heterostructure (DH) wafer are studied by x-ray topography. Such DSD’s are one of the primary sources of the dark-line defects (DLD) that cause rapid degradation of GaAs-Ga1−xAlxAs DH lasers. By using x-ray topography almost all DSD’s observed by photoluminescence topography are correlated with dislocations in a GaAs substrate. In addition, it is observed that some dislocations in the substrate are not sources of DSD’s when the dislocation axes are nearly parallel to the surface of the substrate.

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