Density of localized state of free carriers in amorphous As2Se3 and As2S3 films

Photosensitive donor- and acceptor-like centers of 1.05 eV and 0.76 eV energies from the valence band were revealed by photoconductivity measurements. These energies are constant and independent of light intensity in range 1.5×10⁹-1.5×10¹⁵ quanta/(cm²·s) and of energy of quanta (> 1.50 eV). Wide quasicontinuous energetic distribution of trap centers state density (N(E)) with maximums at 0.62, 0.87 and 1.05 eV for As₂Se₃ and at 0.74, 0.92, 0.99, 1.21 eV for As₂S₃ were found by relaxation measurements of positive and negative charge. N(E) increases in the energy range 0.90-1.05eV as was revealed considering low frequency-capacity dependency in the barrier structure of Al-As₂Se₃.