Structural, Optical and Electrical, Properties of As-Se-Tl Films

Bulk alloys of As-Se-Tl were synthesized by weighting out suitable proportions of the required compositions with purity 5N. Melting them up to 875 C for 16 hours followed by rapid quenching in ice water.Thermal evaporation technique was used to prepare As-Se-Tl films on glass substrates. The produced films have 200 nm thickness. X-ray diffraction and differential scanning calorimetry were used to investigate the film structural properties. The nature of the produced alloys, Glass transition, crystallization temperature and melting point as well as the permittivity of the as-deposited and annealed films up to 373 K were studied as function of Tl-content. Optical constants like dispersion energy, high frequency dielectric constant, lattice dielectric constant, and the oscillator energy were determined. Composition effect on the dc electrical properties was investigated in the temperature range (175-375)K. Hopping conduction dominates at low temperature region (173-300) K. At the high temperature region (300-373) K, band conduction occurs. Seebeck coefficient, a.c conductivity and related constants were determined.