Electrical resistivity and optical absorption of amorphous As2Te3:Ag co-evaporated films are investigated as a function of the Ag content up to 25 at%. The film resistivity decreased from 2.1 × 104 to 2.6 × 102 ω cm and the activation energy for conduction decreased from 0.45 to 0.36 eV with increasing the film Ag content. The dependence of the optical absorption coefficient on the photon energy is ascribed by the relation (αhv) = B(hv − E0)2. The optical gap E0 of the as-prepared films decreases with increasing Ag content. The tail width of the localized states at the band gap was calculated and it increases with increasing the Ag content. The effect of the thermal annealing on the optical absorption was investigated. The changes were attributed to the thermally induced transformations in the chalcogenide films

Electrical resistivity and optical absorption of amorphous As2Te3:Ag co-evaporated films are investigated as a function of the Ag content up to 25 at%. The film resistivity decreased from 2.1 × 104 to 2.6 × 102 ω cm and the activation energy for conduction decreased from 0.45 to 0.36 eV with increasing the film Ag content. The dependence of the optical absorption coefficient on the photon energy is ascribed by the relation (αhv) = B(hv − E0)2. The optical gap E0 of the as-prepared films decreases with increasing Ag content. The tail width of the localized states at the band gap was calculated and it increases with increasing the Ag content. The effect of the thermal annealing on the optical absorption was investigated. The changes were attributed to the thermally induced transformations in the chalcogenide films

Electrical resistivity and optical absorption of amorphous As2Te3:Ag co-evaporated films are investigated as a function of the Ag content up to 25 at%. The film resistivity decreased from 2.1 × 104 to 2.6 × 102 ω cm and the activation energy for conduction decreased from 0.45 to 0.36 eV with increasing the film Ag content. The dependence of the optical absorption coefficient on the photon energy is ascribed by the relation (αhv) = B(hv − E0)2. The optical gap E0 of the as-prepared films decreases with increasing Ag content. The tail width of the localized states at the band gap was calculated and it increases with increasing the Ag content. The effect of the thermal annealing on the optical absorption was investigated. The changes were attributed to the thermally induced transformations in the chalcogenide films

Optical absorption at room temperature and electrical resistivity at temperatures between 200 and 320 K for (As.Te)1-xSex thin films (where x=0.20, 0.23, 0.27, 0.32 and 0.44) have been studied. Increasing the Se content was found to increase the optical energy gap and the activation energy for conduction of the investigated films. The optical energy gap of the As0.40Te0.40Se0.20 films was increased up to 1.21 eV by increasing the film thickness to 120 nm, while thermal annealing at 480 K reduced it down to 0.83 eV. The decrease of the optical gap is discussed on the basis of amorphous-crystalline transformations.

Optical absorption at room temperature and electrical resistivity at temperatures between 200 and 320 K for (As.Te)1-xSex thin films (where x=0.20, 0.23, 0.27, 0.32 and 0.44) have been studied. Increasing the Se content was found to increase the optical energy gap and the activation energy for conduction of the investigated films. The optical energy gap of the As0.40Te0.40Se0.20 films was increased up to 1.21 eV by increasing the film thickness to 120 nm, while thermal annealing at 480 K reduced it down to 0.83 eV. The decrease of the optical gap is discussed on the basis of amorphous-crystalline transformations.

Optical absorption at room temperature and electrical resistivity at temperatures between 200 and 320 K for (As.Te)1-xSex thin films (where x=0.20, 0.23, 0.27, 0.32 and 0.44) have been studied. Increasing the Se content was found to increase the optical energy gap and the activation energy for conduction of the investigated films. The optical energy gap of the As0.40Te0.40Se0.20 films was increased up to 1.21 eV by increasing the film thickness to 120 nm, while thermal annealing at 480 K reduced it down to 0.83 eV. The decrease of the optical gap is discussed on the basis of amorphous-crystalline transformations.

Glassy As45.2Te46.6In8.2 thin films were thermally evaporated onto chemically cleaned glass substrates. Crystallization kinetics were determined under isothermal conditions. Heating the film up to the isothermal temperature with different rates was found to yield films with different electrical characterization. Conductivity of the investigated film was used as a parameter indicating the crystallized fraction χ(t). The obtained values of the activation energy for crystallization, the frequency factor and the Avrami index are (100±0.5) kJ/mol, (7.31±0.04) 108 s−1 and 1.45, respectively. The non-integer value of the Avrami index indicates that two crystallization mechanisms are responsible for the crystal growth

Glassy As45.2Te46.6In8.2 thin films were thermally evaporated onto chemically cleaned glass substrates. Crystallization kinetics were determined under isothermal conditions. Heating the film up to the isothermal temperature with different rates was found to yield films with different electrical characterization. Conductivity of the investigated film was used as a parameter indicating the crystallized fraction χ(t). The obtained values of the activation energy for crystallization, the frequency factor and the Avrami index are (100±0.5) kJ/mol, (7.31±0.04) 108 s−1 and 1.45, respectively. The non-integer value of the Avrami index indicates that two crystallization mechanisms are responsible for the crystal growth

Glassy As45.2Te46.6In8.2 thin films were thermally evaporated onto chemically cleaned glass substrates. Crystallization kinetics were determined under isothermal conditions. Heating the film up to the isothermal temperature with different rates was found to yield films with different electrical characterization. Conductivity of the investigated film was used as a parameter indicating the crystallized fraction χ(t). The obtained values of the activation energy for crystallization, the frequency factor and the Avrami index are (100±0.5) kJ/mol, (7.31±0.04) 108 s−1 and 1.45, respectively. The non-integer value of the Avrami index indicates that two crystallization mechanisms are responsible for the crystal growth

Measurements of absorbance and transmittance in Ge20Se80-xBix (0 x 10 at %) chalcogenide thin films in the visible range at room temperature were carried out. The dependence of the optical absorption on the photon energy is described by the relation hv=B(hv-E0)2. It was found that the optical energy gap E0 decreases gradually from 1.93 to 1.205 eV with increasing Bi content up to 10 at %. The rate of the change decreases with increasing Bi content. The composition dependence of the optical energy gap is discussed on the basis of the concentration of covalent bonds formed in the chalcogenide film. The decrease of optical energy gap with increasing Bi content is related to the increase of Bi–Se bonds and the decrease of Se-Se bonds. The effect of thermal annealing for different periods of time on the behavior of optical absorption of the as-deposited films was investigated. The optical gap increases with increasing annealing time. The rate of change decreases with increasing annealing time, then E0 reaches a steady state. The increase in the values of the optical gap of the amorphous films with heat treatment is interpreted in terms of the density of states model. The structure of the as-prepared and thermally annealed films were investigated using transmission electron microscopy, energy dispersive analysis and X-ray diffraction. It was confirmed that the as-prepared films were in the amorphous state. Phase separation was observed after thermal annealing. The separated crystalline phases were identified.