Table of contents

The advantages offered by ferroelectric films deposited directly onto silicon in memory applications, field effect devices and pyroelectric detectors have stimulated intense research activity. This review covers work carried out during the last several years on their growth, characterization and device fabrication using ferroelectric thin films of on single-crystalline Si substrate with and without buffer layers.

Metallic copper films have been deposited on Si(100) substrates by nebulized spray pyrolysis of Cu(acac), Cu(hfac) and Cu(dpm). The structure and morphology of the films have been examined by x-ray diffraction and scanning electron microscopy. The films are polycrystalline in nature with a preferred (111) orientation. Based on the electrical resistivity data, various transport parameters of the films have been estimated. Growth kinetics and the environmental stability of the films from the precursors have been compared. Taking all the factors into account, Cu(dpm) seems to yield the best films of copper metal.

Auger electron spectroscopy and mass spectrometry have been used to investigate the elemental composition of single-crystalline surfaces subjected to annealing and evaporation in vacuum and to analyse the evaporation products. We found three distinct temperature regimes, within which the surface composition of undergoes different changes: outgassing (T = 300-650 K); surface segregation of Li and O (T = 650-1150 K); and evaporation of Li, and LiO ( K). The evaporation of Nb becomes noticeable only at temperatures close to the Curie temperature (1483 K).

films have been grown by laser ablation on (100) oriented Si and GaAs substrates. Optimal growth of was obtained at a substrate temperature of 450C in a molecular oxygen atmosphere of Torr. X-ray measurements show these films to be (111) oriented, with the growth direction random in the plane of the film. The introduction of (100) oriented, epitaxial MgO buffer layers as thin as 10 Å on the substrates results in the growth of (100) oriented, epitaxial films. X-ray pole-figure measurements on these films indicate that both the and the MgO films are oriented cube on cube on the Si and GaAs substrates, namely . Room-temperature magnetization measurements of the (111) oriented films show that there is good agreement between the magnetic properties of the films grown on Si and on the GaAs substrates. Similar agreement is found for the magnetization measurements of the (100) oriented epitaxial films grown with a MgO buffer layer. Moreover, the hysteresis loops for the (111) and (100) oriented films are very similar, indicating that the epitaxy has not significantly improved the magnetic properties of the . In fact, a small decrease of the high-field magnetization is observed with increasing MgO film thickness.

The problems arising in conventional static light-scattering experiments with turbid samples due to multiple scattering of light can be overcome by the cross correlation technique. We recently reported results of 3D cross correlation experiments in which the angle dependence of the experimentally determined values of the singly scattered light intensity agrees with that of the scattering cross section of the suspended particles. In this paper we present measurements for various optical path lengths of the scattered light and compare the experimental results with Monte Carlo simulations. We demonstrate that the dependences of the singly and multiply scattered light intensities on the optical path length obtained by the 3D cross correlation method are in good agreement with the data obtained from Monte Carlo simulations. These results further confirm that the 3D cross correlation technique indeed allows the direct determination of the singly scattered light intensity by experimental means without any need for the detailed information about the experimental set-up that is necessary in Monte Carlo simulations.

A fast pulsed jet of is applied for the loss modulation of a CW laser and pulse trains of repetitively Q-switched generation are recorded in the frequency range 0.1-1 kHz. The laser-pulse shape and its duration depend on the jet-driving frequency, the position of the pulsed stream relative to the intracavity beam and the temporal changes of the absorber density. A controllable, full-depth modulation of the laser output at frequencies in the range between the jet frequency and harmonics is obtained. The process is ascribed to the interaction of a vortex trail evolving in the jet-edge region. The resulting modulation of the laser gain is ascribed to the common effect of the absorber bleaching and beam refraction.

Experimental results regarding the study of plasma double layers (DLs) by electric and spectral methods in the case of a glow discharge obtained in a chamber of three-electrode geometry are presented. The experimental results prove that the appearance of DLs in active plasmas can be accompanied by quantum processes, such as excitation and ionization.

A pulsed Townsend swarm technique has been used to study electron-ionization and electron-attachment processes in methane over the density-normalized electrical field strength, , in the range 1.2-30 fV (120-3000 Td). The time-resolved ionic avalanches were obtained under conditions such that the occurrence of electron-attachment processes was detected unambiguously. The analysis of these avalanche pulses resulted in values of the effective ionization coefficients and positive-ion mobilities over the above range. To the best of our knowledge, no values of positive-ion mobilities had been published before for Td. The electron-attachment effects were observed up to Td.

We present preliminary results on a low-pressure glow-discharge-based process for the destruction of dilute concentrations of volatile organic compounds. Methylene chloride and benzene were studied in dilute mixtures with Ar, Ne and He rare gases. The destruction efficiency was observed to increase with increasing pressure. This and other observations are compatible with molecular dissociation by dissociative electron attachment to high-lying Rydberg states of molecules produced via excitation transfer from the metastable states of the rare gases.

Many thermal radiation results for a two-dimensional, axisymmetric, atmospheric, free-burning arc for several different wavelength intervals, as well as the entire thermal spectrum, are presented. Quantities such as the emission, average intensity, radiative source term and radial flux are calculated from a theoretically rigorous technique for handling radiative transport in a medium such as a plasma in which the absorption coefficient is a strong function of the wavelength. An S-N discrete ordinates method is used on a line-by-line basis to perform this task. Most of the results presented are for a pure-argon arc; however, results indicating the effect of copper contamination on the radiative quantities are also given. Comparisons between the pure-argon and copper-contaminated arcs show that a small amount of copper greatly affects the radiative characteristics of the plasma.

The effects of interface states on the non-stationary transport properties (capacitance and conductance) of Schottky contacts and metal-insulator-semiconductor (MIS) tunnel diodes are studied. Our study is based upon a detailed analysis of the various carrier-exchange mechanisms taking place at a metal-semiconductor contact and incorporates all the effects of the non-equilibrium and non-stationary population of the interface states. The theory offers an unambiguous interpretation of the experimental results in the whole range of biases and frequencies. The relevance of our results for the determination of the density of interface states from capacitance and conductance measurements and for the evaluation of the effects of the interfacial layer thickness in MIS tunnelling diodes has been considered.

A new glow curve fitting method using the Gauss-Lorentz asymmetric function is suggested. By calculating the thermoluminescence (TL) parameters it is shown that this is compatible with a general-order kinetics model. The relations between TL parameters and fitting function parameters are determined. The new fitting method is tested by computer simulated glow curves. The coefficients of Chen's interpolation-extrapolation formula for calculation of TL parameters are presented in an analytical form. It is shown that the Chen method is a special case of the integral method of TL parameter calculation.