The Effects of Gamma Irradiation on the Optical and Electrical Properties of Melt Quench Ge18Bi4Se78 Chalcogenide Glass.

The structural, optical, and electrical properties of as-deposited and gamma irradiated (50, 100, 150kGy) Ge18Bi4Se78 thin films have been investigated. The structural characteristics of both the as-deposited and gamma irradiated films are inspected by X-ray diffraction (XRD).The optical constants of all the films are analyzed in the wavelength range 250-2500 nm employing spectrophotometer measurements at normal incidence. The type of transition is estimated using the obtained optical constants. The optical energy gap Eop as well as Urbach Eu energy in addition to plasma frequency ωp are studied. Single oscillator and Drude models are used to discuss the refractive index in the normal dispersion region. The effect of γ irradiation on the DC conductivity of the considered films is inspected

Optical and electrical properties of tin-doped cadmium oxide films prepared by electron beam technique

Tin-doped cadmium oxide films were deposited by electron beam evaporation technique. The structural, optical and electrical properties of the films were characterized. The X-ray diffraction (XRD) study reveals that the films are polycrystalline in nature. As composition and structure change due to the dopant ratio and annealing temperature, the carrier concentration was varied around 1020 cm-3, and the mobility increased from less than 10 to 45cm2 V-1 s-1. A transmittance value of ~83% and a resistivity value of 4.4 × 10-4 Ω cm were achieved for (CdO)0:88(SnO2)0:12 film annealed at 350 oC for 15 min., whereas the maximum value of transmittance ~93% and a resistivity value of 2.4 × 10-3 Ω cm were obtained at 350 oC for 30 min. The films exhibited direct band-to-band transitions, which corresponded to optical band gaps of 3.1–3.3 eV

Structural and optical properties of Ge-As-Te thin films

Chalcogenide glasses with Ge10AsxTe90−x (x = 20, 25, 30, 35, 40, 45 and 55 at.%) were prepared by melt quenching technique. The glass transition temperature, the crystallization temperature, the melting temperature and the glass-forming tendency were determined from the differential scanning calorimetry measurements. The structural and optical properties of Ge10AsxTe90−x thin films prepared by electron beam evaporation were studied. X-ray diffraction showed that the as-evaporated films are amorphous and crystallize after annealing depending on the As content. The transmittance and reflectance of the films are found to be thickness dependent. The optical-absorption data indicate that the absorption mechanism is direct transition. The optical band gap values are increased with increasing As content while they decrease with increasing the film thickness. Upon annealing the transmittance and the optical band gap decrease whereas the reflectance and the refractive index increase

Annealing and thickness effects on some electrical and optical properties of Sb:SnO

Effects of annealing and film thickness on the electrical and optical properties of Sb:SnO2 films deposited by electron beam from bulk samples prepared using sintering technique have been investigated. A compromise between low resistivity and high transparency of the film has been studied using the factor of merit. This factor, which has been found maximum for film 100 nm thick annealed at 550 °C for 15 min, seemed to be enhanced with increasing annealing time and/or film thickness confirming the simultaneous improvements of transparency and conductance with the latters. Other optical and electrical parameters such as refractive index, width of energy gap, density of localized states, concentration and mobility of carriers and Seebeck coefficient have been studied also, discussed and correlated to the microstructure changes with annealing and film thickness

Optical and electrical properties of Sn-Sb-Se chalcogenide thin films

The optical and electrical properties of the as-prepared and annealed SnxSb20Se$_{80-x}$ (where x = 8, 10, 12, 13.5, 15, 16.5 and 18 at.%) thin films were studied. X-ray diffraction showed that all the as-prepared Sn-Sb-Se films were amorphous. Annealing the films at 473 K or above crystallized the films and the degree of crystallinity depended on the Sn content. The optical transmittance and reflectance were measured in the wavelength rang 200–2500 nm. The estimated optical band gap was found to decrease with increasing Sn content. A great difference in the optical constants values due to transformation from amorphous to crystalline phase structure of the films were found after annealing. This is advantageous for optical disk data storage applications. It was found that the resistivity decreases with increasing temperature for all the compositions indicating that these films have a semiconducting behavior with thermally activated conduction. The conduction in these films was suggested to be thermally assisted charge carrier movement in the extended states. Annealing the films caused a reduction in the room temperature resistivity by six order of magnitude. This was ascribed to the amorphous-crystalline transformation

Optical Properties of In-Ge-Se Thin Films

Effect of composition and annealing temperature on the optical properties of In 8 Ge x Se 92-x ( 14 ≤ x ≤ 25.5) thin films deposited by electron beam from bulk samples prepared using melt quench technique are investigated and discussed. All films have amorphous structure. It was found that the electronic energy gap E g increases with increasing Ge contents and has an ubrupt change at coordination number Z≥2.65. The ratio of free carrier concentration to the carrier effective mass ( N/m * ) and the high frequency dielectric constant ε ∞ showed also uprupt change at Z ≥2.65. The optical relaxation time τ found to have a minimum value at Z = 2.65. The optical energy gap E g found to be affected by annealing