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Silicon nanotips fabricated by electron cyclotron resonance plasma etching of silicon wafers are studied by spectroscopic ellipsometry. The structure of the nanotips is composed of columns 100-140 nm wide and spaced by about 200 nm. Ellipsometry data covering a wide spectral range from the midinfrared to the visible are described by modeling the nanotip layer as a graded uniaxial film using the Bruggeman effective medium approximation. The ellipsometry data in the infrared range reveal two absorption bands at 754 and 955 cm-1, which cannot be resolved with transmittance measurements. These bands indicate that the etching process is accompanied with formation of carbonaceous SiC and CHn species that largely modify the composition of the original crystalline silicon material affecting the optical response of the nanotips. OCIS codes: 120.2130, 160.1245, 260.2065, 310.3840.

Time-resolved photoluminescence (TRPL) measurements are used to evaluate and distinguish the roles of S diffusion, initial absorber quality and Ad[Cl.sub.2] treatment on recombination in polycrystalline CdTe. Low-temperature PL, cathodoluminescence and scanning electron images have shown how defect chemistry, grain-boundary passivation, and morphology are affected by S diffusion and the Cd[Cl.sub.2] treatments.

An analysis of the mechanisms that cause deviations of the emission current from the input data current in polycrystalline silicon (poly-Si) thin-film transistor (TFT) current copier active matrix carbon nanotube Field Emission Display (FED) pixel circuit is presented. These effects make the modulated emission current sensitive to the processes variations of the circuit elements.

The influence of postdeposition treatments on the doping of large-grained polycrystalline silicon p(super +)nn(super +) thin-film diodes on glass substrates is determined using resistivity and impedance analysis measurements. The results show that accurate control of the doping in large-grained polycrystalline Si films is possible, provided the effects of defects and the necessary postdepression treatments are carefully accounted for.

Presentation of bound on transport coefficients of random polycrystals of laminates is done. The presentation includes the well-known Hashin-Shtrikman bounds and some rigorous bounds involving two formation factors for a two-component porous medium.

Single-crystal silicon and polycrystalline silicon carbide and boron carbide are bombarded with a beam of electrosprayed nanodroplets at normal incidence. The volume of sputtered material is measured with a profilometer and the molecular flux of the beamlet with a time of flight spectrometer and the significant increase with respect to the sputtering rates of broad-beam atomic ion sources is due to the large molecular flux of electrosprays.

Spectrally resolved photoluminescence quenching is shown as a means to determine the exciton diffusion length of many archetype organic semiconductors used in thin film devices. The aggregation and crystal orientation has affected the anisotropy of the diffusion length for vacuum-deposited polycrystalline films.

The optical constants of Pr films are obtained in the 4-1600 eV range from transmittance measurements, where the thin films of polycrystalline Pr are deposited by evaporation in ultrahigh vacuum conditions. The studies have shown that Pr is a promising candidate for filters and multilayer coatings in the energy range below [O.sub.2,3] edge in which most materials have a strong absorption.

Diffraction method is used for examining the structure of polycrystalline [Ni.sub.3]N layers in periodic C/Ni multilayers, where the method is modulated by a standing wave created by the interference of the radiation. This method is used for analyzing the profiles of the crystallize sizes and strains in multilayers.

The terahertz (THz) vibrational spectroscopy of organic polycrystalline thin films is characterized, using a method of waveguide terahertz time domain spectroscopy (waveguide THz-TDS). X-ray diffraction has determined the orientation of the polycrystalline tetracyanoquinodimethane (TCNQ) films on the parallel plate waveguide (PPWG) surface.

The dependence of yield strength, uniform elongation and toughness on grain size in metallic structural materials is examined. The high toughness is obtained in the grain size of several micrometers and hence more attention should be given for developing the metallic materials with grain size of several micrometers for structural applications.

The various geometric considerations for the diffusion in several polycrystalline solids are studied. The results show that though the apparent activation energy is well bounded by the characteristic values for lattice and triple junction diffusions, the apparent grain size exponent can exceed the maximum value.

The change of the optical transmittance for calcinations temperatures are measured at two different sintering temperatures in Nd:[Y.sub.2][O.sub.3]. It is found that optical transmittance is highly dependent on the calcination temperature and hence the calcinations at 1080 and 1100 degree Celsius are suitable to fabricate [Y.sub.2][O.sub.3] and Nd:[Y.sub.2][O.sub.3].