Radiation and Thermal-Induced Defects in Amorphous As4Se3Te3

Abstract

The simultaneous doses of thermal and gamma-irradiation have been used as external perturbations for producing a controllable concentration of defects in a-As4Se3Te3. The investigation is made by systematic measurements of the electrical conductivity (over the temperature range from 350 K down to 77 K), X-ray diffraction (λ = 0.1542 nm), and DTA.Results present evidence for structural defects creation increasing with the dose rate till a saturation value is approached. At thermal annealing temperature Ta = 413 K, a-As4Se3Te3 went to saturation near 1.5 × 106 rad, and for Ta = 493 K at 3 × 104 rad. The change in the X-ray diffraction patterns and the DTA thermograms for samples irradiated at T ≲ Tg = 410 ± 1 K indicate an even relaxed "amorphous" state is produced. Radiation-induced structural transitions, however, have been observed upon annealing near or above the crystallization temperature Tc = 493-535 K, where the activation energy of crystallization is amounted to be 1.2 ± 0.1 eV.