Nanocrystalline PbTe films are deposited on different substrates at room temperature through thermal evaporation. The films are stoichiometric single-phase polycrystalline with 200 texture. Electrical properties of the films are analyzed in the framework of a grain boundary channel conduction model. The index of refraction and extinction coefficient of PbTe films are extracted from infrared spe...

Optical spectroscopy techniques, including visible and near infrared (IR) Raman and synchrotron IR methods have been applied to study solid nitrogen at megabar pressures. We find that nitrogen becomes totally opaque above 150 GPa, accompanied by the disappearance of Raman and IR vibrational excitations, while new broad IR and Raman bands become visible. Optical absorption measurements reveal th...

The foundational Franz-Keldysh effect and Einstein model are applied in this work to characterize semiconductor band-edge absorption---and its departures from ideality. We unify the models fully field-induced tunneling of photoexcited electrons degenerate valence bands into conduction band, with encroachment band gap arising as an Urbach tail. Our unified is implemented for semi-insulating indi...

lipoid proteinosis (lp) is a rare autosomal recessive disease characterized by the deposition of an amorphous hyaline material in the skin, mucosa and viscera. the classic manifestation is onset in infancy with a hoarse cry due to laryngeal infiltration. skin and mucous changes develope, and the disease follows a slowly progressive course. in this case report, a 49 year-old man presented with a...

We report on the optical properties and local bonding configurations of both as-deposited and postannealed hydrogenated amorphous silicon nitride a-SiNx :H thin films grown on crystalline Si substrates with x approximately 1.2±0.1. Ultraviolet optical reflection and infrared IR absorption measurements were applied to characterize the films. A method simply based on optical reflection spectra is...

We study the structural, dynamical, and electronic properties of amorphous Si1−xGex :H alloys using firstprinciples local basis molecular dynamics techniques. The network topology and defects in the amorphous network have been analyzed. Structural changes, particularly an increase in number of defects and strained bond angles, have been found as the Ge content increases from x=0.1 to 0.5. The e...

Silica based glasses are used as nuclear shielding materials. The effect of radiation on these glasses varies as per the constituents used in these glasses. Glasses of different composition of SiO2-Na2OMgO-Al2O3 were made by melt casting techniques. These glasses were irradiated with neutrons of different fluences. Optical absorption measurements of neutron-irradiated silica based glasses were ...

In this review the effects of clustering associated with the sp and sp phases of amorphous carbon thin films are examined. We highlight that many of the optical and electronic properties of these films can be explained by consideration of disorder in the sp phase. Within the context of topological and structural disorder, we explain the variation of the visible Raman line width, Raman shift, Ta...