ZnO and ZnO:Mn nanocrystals synthesized via reverse micelle method. The size, band gap, Urbach energy, optical constants and penetration depth of nanocrystals were calculated by UV-vis spectroscopy data. The surface morphology was studied with the use of scanning electron microscope (SEM). Moreover the samples exposed to Gama ray source of 60Co and their thermoluminescence properties...

In the present study, the oxyfluoride glasses of SiO2-Al2O3-CaF2 system containing different amounts of Y3+ ions were prepared through the convenient melting method. The crystallization temperatures and size of the CaF2 nanocrystals were obtained from DTA curves and XRD patterns, respectively. As a consequence, the optimum amount...

This paper investigates the stability of dilution series of pin and nip microcrystalline silicon solar cells under low-energy proton irradiation (E = 405 keV). Variation of electrical parameters, defect-related absorption and Urbach parameter are investigated as a function of irradiation and annealing steps. Highly microcrystalline cells show a relative efficiency loss of up to 80 % after proto...

Two sets of hydrogenated microcrystalline silicon thin-film samples were prepared by Plasma Enhanced Chemical Vapor Deposition (PECVD) technique at different deposition conditions of excited power and pressure. The correlation between the crystalline volume fraction for the samples determined from Raman spectra and the excited power, pressure, absorption coefficient, refractive index and optica...

thin films of binary bi 0 -teo and bi 0 -v 0 systems were prepared by the thermal co-evaporation technique in a vacuum at room temperature. the optical absorption edge of these systems are studied in the wavelength of 200-800 nm using a perkin-elmer uv/vis spectrophotometer. it is found that the value of n=3/2 in the davis-mott equation is best fitted for the fundamental absorption edge for the...

The density of electron states, p(E), in disordered systems in the band-tail region near band edges is investigated. %'e show that the p(E) of the Halperin and Lax type derived by Sa-yakanit predicts, in three dimensions, an exponential (Urbach) band tail for the correlation lengths found in amorphous Si and within the energy range observed in optical absorption near band edges. The simple expo...

Abstract III-V nitride semiconductors have been characterized by photothermal deflection spectroscopy (PDS) which can provide the information of non-radiative recombination involving defect levels. After understanding challenges applying PDS to materials emitting light, advantages and features were described for evaluating defects level in band gap. The reciprocal slope spectrum near bandgap en...

A general semiconductor-independent two-dimensional character of the carrier distribution in top-gate polymer field-effect transistors is revealed by analysing temperature-dependent transfer characteristics and the sub-bandgap absorption tails of the polymer semiconductors. A correlation between the extracted width of the density of states and the Urbach energy is presented, corroborating the 2...