No abstract

The local atomic order of an amorphous Se(0.90)S(0.10) alloy produced by mechanical alloying was studied by x-ray diffraction and extended x-ray absorption fine structure (EXAFS) data obtained at three temperatures, T = 300, 200 and 30 K. From the cumulant analysis of the EXAFS data, structural properties such as average interatomic distances, average coordination numbers, Debye-Waller factors and anharmonicity, given by the third cumulant, were obtained. The results found indicate that there is alloying at an atomic level, and Se-S pairs are more disordered and distorted than Se-Se ones due to the milling process.

It was concluded that low-level laser therapy (LLLT) of the thyroid gland may affect the level of thyroidal hormones.

We investigated the thermal and photothermal properties of an amorphous GaSe9 alloy produced by mechanical alloying considering the photoacoustic spectroscopy and differential scanning calorimetry (DSC) techniques. The room temperature thermal diffusivity of GaSe9 was determined using the open photoacoustic cell configuration considering the thermal diffusion and thermoelastic bending effects. The glass transition and crystallization processes were investigated through DSC measurements obtained at five heating rates, and glass transition, crystallization temperatures, and activation energies were determined. The crystallization mechanism was also determined.

The eletronic and optical properties of amorphous GaSe thin films produced by vacuum evaporation were investigated using X-ray photoemission spectroscopy (XPS) and transmittance spectroscopy techniques. XPS measurements allowed the determination of the valence band energy and showed the chemical bonding and the charge transfer between Se and Ga atoms. Transmittance measurements allowed the determination of the optical gap, refractive index and extinction coefficient in the low and high absorption regions. Using the Wemple and DiDomenico single oscillator model we also found the oscillator and the dispersive energies. From the valence band and optical gap energies, the conduction band was found and an energy level diagram for f-GaSe is proposed.