Gold films of thicknesses 150-300 Å were deposited on quartz substrata using vacuum evaporation technique. Spectrophotometric measurements of transmission T and reflection R at normal incidence were performed in the range 0.4-3.0 µm. The real and imaginary parts of the complex refractive index ñ were determined using a developer algorithm bashed on Murmann's exact equations. The accuracy in the determined n and k was found to be ±6.0% and ±1.6%, respectively. The dispersion curve of n slowed an anomalous dispersion in the visible region characterized by a peak at λ = 0.840 µm. The dielectric constants were calculated and presented. The Drude model parameters ω_{p} and ω_{τ} and d.c. conductivity were determined and compared. The results showed that such parameters could be obtained from free-electron analysis for the near IR experimental results and the intraband transition contributes significantly to the dielectric functions.
Over the last few years there have been many studies of GaAs layers grown at low temperatures (180-300°C), so called LT GaAs. The interest in LT GaAs was motivated by the potential application of 600oC annealed LT GaAs in microwave and fast optoelectronic devices because of its short photocarrier lifetime, reasonable mobility and high resistivity. These properties are associated with the nonstoichiometry of LT GaAs. Recently, studies of comparable material, nonstoichiometric GaAs produced by arsenic ion implantation have been initiated. There is still a strong controversy as to whether the arsenic antisite (As_{Ga}) or arsenic precipitates are responsible for unique electrical properties of both materials. This paper presents the results of structural and electrical studies of high energy As implanted GaAs and comments on relationships between the structure and the resulting electrical properties.
The studies of transport and optical properties of GaAs implanted with high arsenic doses were performed. As-implanted samples showed hopping conductivity and the exponential absorption tail in the near-IR region. Both effects were probably caused by the amorphization of implanted layer. Using EPR measurements it was found that arsenic antisite defect with high local strain field was created during implantation. Annealing of implanted layers at 600°C led to substantial removal of amorphization, decrease in absorption coefficient and hopping conductivity leading to resistive samples. The possible model of such behaviour may be similar to the one of suggested for low temperature GaAs layers.
The measurements of cold rolled nickel alloys with 1 at.% of Ge, Zn, In, Zr, Pb and additionally Ti and Sb by positron lifetime and Doppler broadening techniques have been done. Monovacancies were a dominating type of defects in the alloys. The authors of the present paper connect the differences between the annihilation parameters of the investigated samples with the existence of the vacancy-impurity atom pairs. A direct proportionality between the vacancy lifetime and the product of vacancy-impurity binding energy and atomic radius of impurity atom has been found.
Weighted difference curves have been shortly presented as a proper tool allowing to analyze in another way two-detector Doppler spectra regarding positron annihilation with admixture electrons in some nickel alloys. The analysis of low and middle momentum parts of Doppler spectra for investigated alloys reflects the annihilation of positrons with admixture electrons. There is no distinct signal of annihilations with admixture electrons from the positron lifetime data for well-annealed samples.
Within the anisotropic BCS model the temperature dependence of the electron Raman light scattering in normal metals and superconductors is investigated. In either case analytical expressions describing the intensity of scattered light as a function of the Raman frequency and temperature are derived.
Nanoparticles of hydroxyapatite (HAp) or tricalcium phosphates (TCP) connected with fibrous phase create biomimetic system between the natural fibrous and ceramic materials building a bone. Chemical bonding between the implant and host tissue takes place through the phosphate layer, which is created on the bioactive implant surface when in contact with the body fluids environment. The Fourier transform infrared spectroscopy can yield microstructural information on the segment level complementary to the morphological information acquired from X-ray scattering as well as electron microscopy. The Fourier transform infrared method is applied to study thin films on different substrates. Moreover, the Fourier transform infrared microscope technique allows to obtain surface and cross-section maps in reflection and transmission modes. This leads to visualization of chemical imaging between substrates and films. In this work, the coatings with different addition of nanohydroxyapatite were deposited by electrodeposition method on titanium and Ti6Al4V alloys. Additionally, sublayers, such as TiO_2, were used to increase hydroxyapatite coating adhesion. The selection of suspension composition, depositing time and layer heat treatment conditions have the conclusive influence on the films parameters. All these experimental parameters were monitored during the sample preparation procedure. Changes in phase composition of biomaterials were determined by the Fourier transform infrared reflection technique based on focal plane array detection system. It has been found that results obtained by the Fourier transform infrared spectroscopy show the differences between the studied samples as well as that optimum time of HAp deposition was 90 s.
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