Thin films of AgInTe2 were prepared on quartz substrates by a flash evaporation technique at substrate temperature ~303 K. The compositions of both the bulk and thin films, with thickness (~208–350 nm), were checked using energy dispersive X-ray spectroscopy (EDX). X-ray diffraction (XRD) measurements showed that AgInTe2 compound is characterized by a tetragonal structure while the as deposited films have amorphous nature. On annealing at 423 and 573 K (for two hours and under vacuum ~10−3 Pa), the films were identified to be single-phase, polycrystalline with a preferred (112) orientation. The optical properties of the films were investigated using spectrophotometric measurements of transmittance and reflectance at normal incidence in the wavelength range (~500–2500 nm). The refractive index (n) and the absorption index (k) of AgInTe2 were determined from the absolute values of the measured transmittance and reflectance. It was found that both (n) and (k) depend markedly on the temperature of heat treatment. The dispersion of refractive index in AgInTe2 was analyzed using the concept of the single oscillator model. Within this concept some dispersion parameters were determined for as deposited and annealed flash evaporated AgInTe2 films at 423 K for 2 h. The calculated values of β indicated that AgInTe2 films belong to ionic class. The ratio of the free carrier concentration to the effective mass (N/m*) were, also determined. The analysis of the absorption coefficient indicated that, this ternary chalcopyrite compound has three allowed direct transitions corresponding to three energies gaps Eg1, Eg2 and Eg3. The crystal field (Δcf), the spin orbit (Δso) and the deformation potential (b) were calculated for both as deposited and annealed flash InAgTe2 films at ~423 K for 2 h.

In our previous work we investigated numerically the influence of the steric properties of conducting particles in a non-conducting host matrix on the electrical conductivity threshold of the material, especially in regard to the shape and orientational order of the particles. In the present work we consider theoretically some additional geometrical aspects of the percolation problem. As regards the percolation threshold itself, we consider three aspects: the probability of inter-penetration of half-soft conducting particles for different penetration depths (penetration probability function), different kinds of inhomogeneous distribution of particles in non-conducting host, size effects, and the agglomeration of conducting particles. We also analyze the size of the conducting-particles' clusters below and above the percolation threshold and compare some characteristic critical exponents with the results in the literature.

Modification of the non-assisted gas flow-line across the target surface in a Grimm-type glow discharge source is described. The new flow–line permits the gas to flow through a cylindrical annular space ending with a disc-space annular gap, facing the target surface. This configuration would cause directed jet assisted gas flow rays to impinge on infinite points across the cathode surface. Improvement has been achieved in the V-I characteristics where $\Delta V$/$\Delta I$ increases from 1.8 to 3.5 V/mA. The sputtering as well as simultaneous deposition rates, have been increased by a factor of 16 and 17 respectively. These roll over with increasing sputtering time, their maximum values at a characteristic time, toc of 21 min. The toc value was constant for different operating parameters provided that the source geometry assembly is kept fixed. The presence of a glass substrate in the anode cavity has, apparently, no effect on the obtained data. Improvements have also been achieved in the crater profile, characterized by an approximately flat crater bottom with nearly vertical walls, and less re-deposited particles on the crater depth and edge. Fixing the distance Z of the substrate from target surface, along the cell axis, and varying the deposition time from 1 to 30 min, a sequence of changes in the deposited film were observed by X-ray diffraction and energy dispersion X-ray (EDX). These changes start with an amorphous structure, followed by the appearance of Cu and Zn crystallites and a probable deposition of Cu5Zn8 clusters. The profile of the number of sputtered particles at different Z values is characterized by a number of peaks and troughs. This behavior has been explained by the occurrence of local cluster-dissociation and formation, by different collision processes. The improvements achieved by the application of the present jet assisted gas flow can be of value in the analytical application of this type of glow discharge.

In spite of the extensive experimental investigations reported in the literature on porous alumina templates, the theoretical mechanisms, and their dependence on process parameters such as potential difference, current density and electrolytes, are not well understood. A theoretical model developed and published for porous structure formation under constant current electrochemical anodization of aluminum is adopted for constant voltage anodization. The model is based on the rate equation approach in which both the alumina formation and etching are considered. The model employs a minimal number of parameters and yet captures the essence of the experimental observations. The model yields an analytical solution relating the model parameters, process parameters and thickness of the film, which is easy to interpret and use. The results of normalized current versus time obtained from the model are in good agreement with the experimental results reported for a range of voltages, 20–40 V. It is also observed that the thickness of the Al2O3 pore follows V1/2 behavior for anytime during the anodization.

We examine numerically the effect of quasiperiodicity in the nature of the states in Fibonacci semiconductor superlattices by means of the transfer matrix formalism. We are interested in the GaAs/AlxGa1 − x As layers, having identical thickness, where the aluminium concentration x takes, two different values. We have found that each miniband of the periodic superlattice splits in several sub-minibands, that is small minigaps appear. We demonstrate that the origin of these small inner minigaps is due to the loss of long-range quantum coherent of the electrons wave. The corresponding electronic spectrum shows a high fragment. The states having transmission coefficient close to zero in the minibands can be viewed as consisting of singular localised states.

Developing the ability to characterize photon statistics of light sources has been one of the important driving forces of Quantum Optics. Photon statistics is also a crucial parameter to evaluate of quantum key distribution security. As practical quantum cryptographic systems encode information on faint laser pulses, we present a simple method to measure and calibrate their intensity noise with respect to shotnoise reference. The technique is based on the record of photodetection timetags in the photon counting regime. Two different methods are considered to produce light pulse: first, direct pulsing of a laser diode driving current, second, chopping the CW laser beam emitted by a laser diode with an acousto-optical modulator. As predicted by basic Quantum Optics theory, levels of attenuation used in practical quantum key distribution systems lead in both cases to Poissonian photon number distribution in the generated light pulses.

Collective effects in the radiation emission via Thomson back-scattering of an intense optical laser pulse by high brightness electron beams are analyzed. The micro-bunching of the electron beam on the scale of the wavelength of the emitted radiation and the consequent free-electron-laser instability may significantly enhance the number of photons emitted. Scaling-laws of the radiation properties, both in the collective and incoherent spontaneous regimes versus laser and electron beam parameters are discussed in the framework of the one-dimensional model.

A method of heat-assisted magnetic recording (HAMR) is characterized. The recording medium is a high coercitivity, granular and perpendicular CoNi/Pt multilayered film. Emission current from a scanning tunneling microscope (STM) is the heating source. Experiments show that an average mark size of 90–120 nm is achieved. A model for achieving 1 terabit/sq.in. recording density (or a mark size of 25 nm) is proposed to guide future effort.

We have studied the characteristics of a plasma reactor for the promotion of chemical reactions aimed to hydrogen reforming from gaseous hydrocarbons. A plasma torch-like electrode configuration was powered by a limited current, high voltage DC source. Using as process gas an argon/methane mixture at atmospheric pressure, we have produced an intermittent spark discharge which has been investigated at different operating parameters. Experimental information on the discharge have been used to perform a numerical simulation of the plasma chemical kinetics. The evolution of the gas-phase composition during and after the interaction in the discharge region was calculated under different operating conditions. The results have been used to predict the hydrogen production yield in the experiments and to study the role played by the different discharge parameters in order to determine the optimal interaction between plasma and gas mixture.

This paper presents an uncertainty budget of measurement on the optical phase on the basis of a metrological analysis inspired from the “GUM” approach [GUM, Guide to the expression of Uncertainty in Measurement (ISBN 92-67-20188-9, 1993)]. This budget takes account of the procedure implemented in calibrating the phase-shifting device and in the actual phase measurement. This study leads to deriving an estimation of the standard uncertainty in measuring the optical path difference at approximately $\lambda/98$. This value agrees with a purely experimental estimate [F. Taillade, Association de la shearographie et des ondes de Lamb pour la détection rapide et quantitative des délaminages, Ph.D. thesis, Technical Note ONERA, NT 2001-3, 2001], which led to a standard uncertainty of roughly $\lambda/108$.