The effect of annealing on the physical properties of DC and RF sputtered ITO thin films has been investigated. Two series of samples were deposited onto glass substrates, the first one consists of several In2O3:Sn (ITO) prepared by DC reactive sputtering with different partial pressure of oxygen (ppo); in the second one, the ITO samples were done by RF sputtering with different RF powers. Annealing experiments were done in various conditions: in air, in vacuum and in Ar atmosphere for temperatures in the 100 °C to 500 °C range. Structural properties were studied using Scanning Electron Microscopy (SEM), the usual X-ray diffraction (XRD) and also in-situ X-ray diffraction where X-ray spectra were recorded while the sample was being annealed. The optical properties were inferred by means of a spectrophotometer with wavelength in the 200–900 nm range. It was found that, for DC sputtered films, annealing favours the existing texture either $\langle 111\rangle$ or $\langle 100\rangle$ ; while, for the RF sputtered ones it always favours the $\langle 111\rangle$ texture. Annealing induced some similar changes in both series of samples such as the increase of grain size, the decrease of the strain and the electrical resistivity. The values of the optical transmission decreases after annealing at temperatures T = 400 °C and T = 500 °C for the DC and the RF sputtered films respectively. The decrease seems to be more important in the DC than in the RF sputtered ITO films.

Organic field-effect transistors (OFETs) in which the active semiconductor is made of polycrystalline octithiophene (8T) were fabricated and characterized. Several methods have been used to extract the parameters of the polycrystalline (8T) transistors as function of gate voltage at room and at low temperatures. These parameters such as the mobility, the threshold voltage, contact resistance and density of traps are extracted from the current-voltage characteristics of OFETs. The first method consists of deriving the drain current as function of gate voltage (transconductance), leading to the so-colled field effect mobility. It appears that the data must be corrected for the substantial source and drain contact resistance. In the second method, the carrier mobility has been corrected for the contact resistance. It is found to increase quasi linearly with gate voltage. Therefore, the contact resistances have been directly extracted from the experimental channel conductance. In the third method, data are interpreted according the multiple thermal trapping and release model using a power law dependence of the mobility with gate voltage together with a constant resistance. Finally, using a model where charge transport is limited by trapping and thermal release at localized states located at grain boundaries, the barrier height at grain boundaries in polycrystalline octhithiophene FETs has been estimated. It is shown that is gate bias dependent.

Hydrogenated diamond-like carbon (DLC:H) films were deposited on Si substrates by a methane (CH4)-argon (Ar) plasma enhanced chemical vapor deposition (PE-CVD) technique assisted by carbon (C) sputtering. The deposition rates of DLC:H films increased with increasing Ar gas flow rate under a CH4 gas flow rate, and saturated at large Ar gas flow rates. The dielectric constants varied from 2.2 ε 0 on DLC:H films deposited without Ar gas flow to 6.3 ε 0 on DLC:H films deposited with large Ar gas flow. The C – V curve for the sweep of bias voltages from positive to negative was positioned above that of the return sweep of bias voltages from negative to positive because electrons are injected from Si substrates to the surfaces of DLC:H films. The C – V curve on the returning bias voltage sweep approached that of the going bias voltage sweep accompanying to an increase in dielectric constant.

The thermal conductivities of nine different synthetic garnet laser crystals at various temperatures, range from 273 to 393 K have been investigated by instantaneous measurement method. The results show that the thermal conductivity of each crystal decreases exponentially with the temperature increasing. It is notable that, different host crystals, such as YAG, GGG, and GSGG have different thermal conductivity, which is attributed to the crucial influence of crystal structure and composition on the absolute value of their thermal conductivity. Moreover, with respect to the same host crystals, the impurity scattering also results in the change of their thermal conductivities. This is because that a higher concentration of doped ions leads to a more phonon scattering modes, which results in a shorter mean free path of the phonons and a lower thermal conductivity. In addition, different host crystals have various dependences of thermal conductivity on dopant concentration. This works provides reliable and useful information for designing high power, high quality, and high stability laser devices.

A metamaterial with a negative effective index of refraction is made from a three-dimensional hexagonal lattice photonic crystal with a metallic basis embedded in foam. It has been simulated with Ansoft HFSSTM in a frequency range from 7.0 to 12.0 GHz. Simulated results tested experimentally and negative refraction verified in some frequencies. Experimental results are in good agreement with simulations.

Intra-dot inter-layer magnetostatic coupling have been investigated in trilayers which consist of two [Co/Pt] multilayers with out-of-plane anisotropy and different coercivities separated by a thick Pt layer. For single domain nanodots, the strong intra-dot inter-layer magnetostatic interactions manifest as a shift of the soft layer hysteresis loop. The amplitude of this shift decreases when the size of the dots is increased and/or when the temperature is increased. Satisfactory agreement is found between calculations and experimental results.

Polycrystalline halosulphate phosphors are prepared by a wet chemical method. Strong thermoluminescence (TL) was observed in KZnSO4Cl, KMgSO4Cl, Na3SO4F and NaMgSO4F hosts. In these hosts Ce, Dy; Ce, Mn and Ce, Tb the Ce3+ ions acting as sensitizers and Dy3+, Mn2+and Tb3+ ions as activators. The TL glow curves of these halosulphate phosphors exposed to γ-rays for 5 Gy at the rate of 0.995 kGyh-1 are described and discussed first time here.

New microwave electronic technology challenges require the integration of many passive components onto chips. Among them, isolators and circulators are non-reciprocal passive devices that contain magnetic materials. It is therefore important to know the magnetic properties of suitable materials. The permeability tensor is the most important parameter to define, because it governs the interaction between the electromagnetic wave and the material, and is thus the origin of all magnetic phenomenons. Our work consists of performing the characterization of thin films of BaM and YIG over a frequency range of 0.4 GHz to 65 GHz. The work shows the presence of a gyroresonance phenomenon and locates the resonance frequencies. The technique is based on S parameter measurements on the magnetic materials performed with a network analyser and a probe tester. Polder's model is used to calculate the different elements of the permeability tensor, which consider the ferrite in its saturated state.

In this paper, the modeling and study of a new non-linear hybrid current controller is presented. It ensures high dynamic response of the current loop with a fixed switching frequency operation mode, a zero static error and high robustness properties as regard to system parameters variations. To model the proposed non-linear current controller, different tools are developed. In a first step a high frequency average model is proposed. It allows studying the average dynamic properties such as bandwidth, time response and overflow. To investigate the behavior of the current ripple due to the switching effect, a second model, based on the construction of a three-dimensional bifurcation diagram and the definition of a form function is established. This model allows studying the nature of the cycle described by the state trajectory and proving that the system operates with a fixed switching frequency. Design rules of the control parameters of this controller are explained and its robustness properties are tested by numerical simulations and experimental tests.

A study of compressibility effects on structure and evolution of a sheared homogeneous turbulent flow is carried out using rapid distortion theory (RDT). The focus of this paper consists in validating RDT code by considering the direct numerical simulation (DNS) and RDT results of Simone [Simone, Coleman and Cambon, Fluid Mech. 330, 307 (1997)]. We will use this theory to clarify the physics of the compressible turbulent flows. An analysis of the behavior of different terms appearing in the turbulent kinetic energy and the Reynolds stress equations permit to well identify compressibility effects which allow us to analyze performance of the compressible model of Fujiwara and Arakawa concerning the pressure-dilatation correlation. The evaluation of this model stays in the field of RDT validity.