OPTICAL PROPERTIES OF AsSeTl THIN FILMS DEPOSITED BY e-BEAM EVAPORATION TECHNIQUE

Five compositions of the system As25 Se75-x Tlx (x = 12, 16, 20, 24 and 28%) have been prepared using melt quench technique. Thin films of the same thickness (200 nm) were deposited by electron beam evaporation technique. Optical and other parameters of the films have been studied. The optical band gap Eop found to decrease by increasing the coordination number r and average number of bonds per atom Nav and by decreasing the heat of atomization Hs. Other parameters as an oscillator energy Eo, dispersion energy Ed and plasma frequency ωp found to be affected by changing thallium content.