The intersubband absorption in symmetric double quantum wells under the laser field is theoretically calculated within the framework of the effective mass approximation. Results obtained show that intersubbband optical transition and energy levels in double quantum well can significantly be modified and controlled by intense laser field. This statement gives a new degree of freedom in various device applications based on the intersubband transition of electrons.

Anisotropic etching of silicon is achieved in the presence of ultra-violet exposure in a solution containing hydrofluoric/nitric/acetic acids (HNA). The HNA solution is typically used for polishing silicon and etching polysilicon due to its isotropic etching property. In the technique proposed in this paper which is called UV-HNA, the etching of silicon is enhanced in the direction determined by UV exposure. A mixture of HF/HNO3/CH3COOH with a relative composition of 1:15:5 seems suitable for revealing 〈111〉 planes with an etch rate of 10 μm/h at 35 °C. The bottom of the etched craters is hillock-free and etch rates as high as 60 μm/h can be achieved using higher concentration of HF acid in HNA solution. In the latter case the etching is more isotropic and mask undercut is observed. Also membranes with a depth of 400 μm are fabricated on n-type Si 〈100〉 with a thickness of 500 μm by means of standard 34 wt% solution of KOH at temperature of 60 °C. Problems encountered during the experiment, and their solutions are discussed and results of these experiments are reported.

Indium oxide (In2O3) violet photodiodes were fabricated. The In2O3 layers were from oxidation of InN deposited by magnetron reactive sputtering. It was found the photocurrent approximately 5.06 × 10−4 A at a bias of 2 V and a photocurrent to dark current contrast ratio higher than around two orders of magnitude. The reverse leakage current prior to breakdown is around 10−5 A. The photodiodes exhibited a narrow responsive region at wavelength from 400 nm to 440 nm. The values of responsivity and quantum efficiency (QE) at 420 nm at biases of 2 V were 0.1985 A/W and 58.62%, respectively.

The thermal conductivity and the interface thermal contact resistance of four different in thickness CuO films, obtained by PVD on a tungsten carbide substrate were investigated with a developed modulated photothermal method based on infrared measurement. According to the knowledge of the substrate thermophysical properties, the gain between the thermal perturbation and the response of the sample was used as the experimental data. The results show the dependence of the effective longitudinal thermal conductivity on the film thickness. Scanning electron microscopy observations reveal the strong anisotropy and columnar structure of the deposits. Moreover, the chemical composition of films was tested. A similar composition for each film was also verified.

Manganese-doped cadmium sulfide nanoparticles are synthesized in a flexible polymer matrix (synthetic rubber) by a chemical route. They are bombarded with 80-MeV oxygen ions having electronic energy loss (S e ) dominant over nuclear energy loss (S n ) and with fluence variation 1011–1013 ions/cm2. Piling up of nanoparticles along certain direction was observed in atomic force microscopy (AFM) images of irradiated samples. Such elongated nanostructures are as a result of nanoparticle growth during ion passage through the samples. Specifically, elongated structures in the form of nanoneedles, nanochannels and nanorods have been observed. The fluence dependent photoluminescence spectra (PL) show significant luminescent peaks at 445 nm and 706 nm, respectively which are tunable with ion fluence. Such a tunability could be promising as lasing materials in nano-luminescent devices and laser diodes. Further, detection of efficient third harmonic generation (THG) in these samples (by using irradiation of a Cr:fosterite laser) could be promising in nanoscopy and nonlinear optics.

In this paper an analysis of optical fiber chromatic dispersion in noisy interferometric system is introduced. The interferometric relative intensity noise (IRIN) is derived in interferometric systems, by considering all effects such as the optical fiber chromatic dispersion and white noise applied to light from a laser diode. The direct relative intensity noise (RIN) is compared with the RIN caused by phase-to-intensity noise conversion. Numerical calculations reveal that the optical fiber chromatic dispersion can enhance significantly the IRIN magnitude and lead to a shift of the IRIN dips. The results can be employed to estimate the influence of the chromatic dispersion in phase-to-intensity noise conversion, which use either self-delayed interferences or interferometers.

Ba doped PLZT ceramic compositions with formula Pb0.982−z La0.012Δ0.006Baz (Zr0.55Ti0.45)O3 for z = 0 to 6 mole% are synthesized by mixed-oxide method. Powder XRD studies indicate the coexistence of rhombohedral and tetragonal phase in 5 mole% Ba doped PLZT composition. SEM pictures show grain size control as Ba concentration increases in PLZT system. $\varepsilon_{rt}$ and tan δ are increased up to 4 mole% and 5 mole% Ba doped PLZT composition respectively. Dielectric maximum ( $\varepsilon_{T_C}$ ) is decreased to 4 mole% Ba doped PLZT and Curie temperature (T C ) is decreased with increase of Ba concentration in PLZT system. Coercive field (E c ) has shown gradual enhancement over series. Remanent (P r ) and spontaneous (P s ) polarizations are decreased to 5 mole% Ba doped PLZT composition.

The relaxor ferroelectric ceramics of La doped xPb(Mg1/3Nb2/3)O3-(1 − x)Pb(Zr0.55Ti0.45)O3 are synthesized by columbite precursor method. Powder X-ray diffraction patterns of these compositions indicate pseudocubic phase formation. Grain growth is inhibited with La doping and is increased with PMN concentration in PMN-PZT ceramics. $\varepsilon_{RT}$ and tan δ are increased to 1.5 mole% La doped PMN-PZT compositions while $\varepsilon_{T_C}$ and T C are decreased with La modification in PMN-PZT system. Pure and La modified 0.8PMN-0.2PZT compositions have shown the most promising relaxor behavior useful for multilayer capacitor (MLC) applications. The ferroelectric properties (E c , P r and P s ) are increased to 1.5 mole% La doped PMN-PZT composition.77.84.Dy Niobates, titanates, tantalates, PZT ceramics, etc.

In order to save the computing time of Monte Carlosimulation, traditional null collision method is improved in whichonly one cross section needs to be evaluated at each collisionspeed. By this method, the electron swarm parameters such aseffective ionization coefficient, $\bar{\alpha}$ , drift velocity and diffusioncoefficient of SF6 and CF4 gas mixtures are calculated overthe E/N range from 150 Td to 500 Td. A set of electron collisioncross-sections that gives transport parameters in agreement withmeasurements for the pure gases is used. The simulation results arethen compared with our experiment data, and show excellentagreements.

Magnetostatic forces computation can be done numerically through Finite Element Analysis by applying the virtual works method on either the energy or the co-energy. They can also be computed analytically using Maxwell's tensor. Different results have been obtained using these two procedures. In this work we will introduce a general way of obtaining magnetostatic stress tensors (Maxwell's tensors) from either the energy or the co-energy. Both tensors are equivalent in induced magnetisation media (media whose magnetisation depends on an external magnetic field), but they are different in permanent magnets (media whose magnetisation does not depend on an external magnetic field). In these media, normal components of the surface forces derived from either the energy or the co-energy are the same, but tangential components have different modules, keeping the same direction as the tangential components of magnetic field H or magnetic induction B respectively. Force density is also different. Forces computed from co-energy do not have the same conservative characteristic as forces computed from energy. The application of Maxwell tensors in the calculation of forces over the real surface of magnetic media must take into account the discontinuity of the forces from one medium (particularly a vacuum) to another. Generally, normal stresses in all media, obtained from the energy and the co-energy, are discontinuous, while tangential stresses are only discontinuous in processes derived from the co-energy in permanent magnets.

The explicit incompressible algebraic Reynolds stress model proposed by Gatski and Speziale [J. Fluid Mech. 254, 59 (1993)] has been extended to be applied to compressible turbulent flows. This extension is based on the modeled compressible transport equations for the Favre-averaged Reynolds stress tensor. The resulting model is tested in a variety of compressible turbulent flows which include the homogeneous shear flow and the compressible mixing layer. Comparisons between the present model predictions and the results of direct numerical simulations and experiments are quite encouraging.