The role of thermal treatment on the optical properties of Ge0.15Se0.85 system

Abstract

a b s t r a c tThe Ge 0.15 Se 0.85 alloy has been prepared in evacuated quartz tubes. Thin amorphous film of Ge 0.15 Se 0.85 system has been prepared by using thermal evaporation technique with 400 AE 5 nm thickness. Atomic absorption spectroscopy (AAS) was used to determine the concentration of the composite elements (Ge and Se). Amorphous structure was observed for prepared films by using X-ray diffraction (XRD). The optical properties of Ge 0.15 Se 0.85 system have been studied as a function of annealing temperatures (T a ¼ 300, 350, 400 and 450 K). The results showed that optical transitions are direct and indirect. The energy gap E g increased with increasing annealing temperature, i.e the absorption edge shifts to lower wavelength. The refractive index, extinction coefficient and real and imaginary parts of dielectric constant for these films vary with heat treatment. Outcome of our study confirms that this system may be used for photovoltaic devices.

The Effect of Annealing on Some Optical Properties in Se-Te-Ag Glasses

“…Increase of the optical bandgap can be attributed to decrease of the width of localized states near the mobility edges so the disorder and defect present in the structure decreases. Increase in optical energy gap E g after annealing at the temperature below the glass transition temperature was also observed in chalcogenide film [17,18]. As the temperature increases, the amorphous nature decreases, disorder increases and the region of strong fluctuations become more and more small.…”

Effects of laser irradiation on optical properties of amorphous and annealed Ga15Se81In4 and Ga15Se79In6 chalcogenide thin films

“…Nemec and Frumar [17] have investigated the irreversible photoinduced changes in As 48 S 52 amorphous thin films prepared by pulsed laser deposition. The work on electronic and structural changes induced by irradiation or annealing in pulsed laser deposited As-Se films by Kalyva et al [18], photoinduced effects in chalcogenide thin films under irradiation by synchrotron light by de Moura et al [19], laser-induced amorphization and crystallization on Se-Te-Pb thin films by Khan et al [20], the role of thermal treatment on the optical properties of Ge-Se system by Alnajjar [21], laser irradiation of amorphous thin films by Ortiz and Blatter [22] are also worth mentioning. The present communication reports the effect of laser irradiation on optical properties of amorphous and annealed thin films of Ga 15 Se 81 In 4 and Ga 15 Se 79 In 6 chalcogenide glasses.…”