Effects of annealing temperatures on optical and electrical properties of vacuum evaporated Ga15Se77In8 chalcogenide thin films

摘要: Abstract The optical constants (absorption coefficient, band gap, refractive index, extinction real and imaginary parts of dielectric constants) amorphous thermally annealed thin films Ga 15 Se 77 In 8 chalcogenide glasses with thickness 4000 A have been investigated from absorption reflection spectra as a function photon energy in the wave length region 400–800 nm. Thin were for 2 h at three different annealing temperatures 333 K, 348 K 363 K, which are between glass transition crystallization temperature glasses. Analysis data shows that rule non-direct transitions predominates. It was found gap decreases increasing temperature. has observed value coefficient increases while values index decrease is explained on basis change nature films, to crystalline state. dc conductivity also reported range 298–393 K. conduction due assisted tunneling carriers localized states near edges. increase corresponding activation present system. These results analyzed terms Davis–Mott model.