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A Monte Carlo (MC) model is developed for understanding the avalanche phenomenon in HgCdTe infrared avalanche photodiodes and also the affect of physical and technological parameters. A comparative study is used for explaining the effect of different combinations of scattering processes on the avalanche phenomenon in HgCdTe.

The properties of stimulated Rayleigh-Bragg scattering (SRBS) from a two-photon absorbing CdSe-Cds-ZnS quantum-rods (QRs) solution in chloroform are studied. The measurements for output/input characteristic curve showed that the backward SRBS could enhance the optical power to limit performance that is based on two-photon absorption, backward stimulated scattering and other nonlinear absorption mechanisms.

The temperature dependence of the photoluminescence (PL) decay time and the influence of the ground state exciton fine structure on the radiative decay time for a nanocrystal material with cubic crystal structure are described. It is shown that the exciton decay is intrinsically a stretched exponential decay due to energy degeneration of individual nanocrystals fluctuations in the confinement potential within the nanocrystal ensemble.

Abstract -- The determination of Pb and Cd by electrothermal atomic absorption spectroscopy with the slurry sampling of carbonized samples into a graphite furnace was considered. Textural and chemical properties [...]

Abstract -- The reduction of indium(III)-Eriochrome Red B complex is studied in wide ranges of pH and concentrations by cyclic voltammetry with a linear potential sweep. The ratio of components [...]

The photodegradation of the films was investigated quantitatively by measuring the photoluminescence (PL) efficiency as a function of the irradiation time and temperature for various intensities. Comparison of the degradation of the glass films in air and in an Ar atmosphere revealed that the main mechanism of photodegradation of the green-emitting nanocrystals (NCs) was oxidization from the first electronically excited state.

The sterically crowded isoindoline pincer ligand, 6'-MeLH, prepared by condensation of 4-methyl-2-aminopyridine and phthalonitrile, displays different reaction chemistry with Cd(super 2+), Zn(super 2+), and Pd(super 2+). It is noted that for Cd(II) and Pd(II) other coordination modes of this ligand are possible, where as for Zn(II) loss of a pyridine arm through solvolysis and subsequent coordination of the remaining fragment is favored.

The synthesis and characterization of photonucleases N,N'-bis[2-[bis(1H-imidazol-4-ylmethyl)amino]ethyl]-3,6-arcidinediamine and N-[2-[bis(1H-imidazol-4-ylmethyl)amino]-3,6-acridinediamine, consisting of a central 3,6-acridinediamine chromophore attached to 4 and 2 metal-coordinating imidazole rings, respectively, are reported. The data indicates that buffer, pH, Hg(II), Fe(III), Cd(II), Zn(II), V(V), Pb(II), and light can be used to tune DNA cleavage by N,N'-bis[2-[bis(1H-imidazol-4-ylmethyl)amino]ethyl]-3,6-arcidinediamine under physiologically relevant conditions.

A report on the preparation and structural characterization of CdSe nanocrystals, which are covered by a multishell structure from CdS and ZnS, is presented. It is found that the CdSe/ZnS core shell particles are irregular in shape and the fluorescence quantum yield decreases for large shell thickness due to lattice imperfections.

The photophysical properties of the newly synthesized starlike CdS are investigated, which was prepared from the lyotropic triblock copolymer solution. It is concluded that the starlike CdS shows the photogenerated charge carriers' diffusion from the tip edge of the conical nanolobes to the thicker inner part including the core, likely as the light-harvesting system of the organic dendrimer.

A method called pseudo steady-state titration is discussed for determining the precipitation pH of nanocrystals coated by electron-donating ligands. It was found that the precipitation of the nanocrystals is caused by the dissociation of the nanocrystals-ligand coordinating bonds from the nanocrystals surface.

Several distinct oxidation and reduction peaks in the voltammograms were demonstrated by electrochemical studies of thiol-capped CdTe nanocrystals inaqueous solution with the peak positions being dependent on the size of the nanocrystals. An extraordinary behavior is found for the oxidation peak observed at less positive potentials.

This article shows that the temperature dependence of minority carrier lifetime in mercury cadmium telluride (HgCdTe) samples of differing dislocation densities can be accounted by including the dislocation contribution in addition to the contribution of well known radiative, auger, and Shockley-Read recombination mechanisms.

Small- and large-angle x-ray scattering experiments are performed on CdTe/MnTe superlattices. The effective MnTe concentration, directly determined from the refractive index profile, is successfully used to simulate the structured nonspecular scattering, and to determine the lateral correlation length of the interface roughness (about 1500 plusminus 750 Angstrom).

A large decrease in the electrical resistance of the junction is observed with an applied voltage of several volts in small area ramp-type junctions. The lower resistivity can be reached using an electrode with a lower resistance.

Several photoluminescence (PL) measurements are conducted to study the defects observed in the close-space-sublimation grown polycrystalline cadmium telluride layers. The impact of the different posdeposition treatments on the PL spectra of the layers is also analyzed.

The synthesis, structure, as well as the optical and magnetic properties of the different Cu-doped [Zn.sub.1-x][Cd.sub.x]S nanoparticles are discussed. These nanoparticles are shown to be extremely ferromagnetic in nature at a temperature of 5 K.

The article presents a new technique, which employs the different light extraction features for the formation of down-converted light-emitting diode (LED). The methodology is shown to be extremely beneficial for the extraction of light in the conventional LED structures.

The significance of the misfit strain in the formation of dark line defects (DLDs) and stacking faults (SFs) in the II-VI green color converters is analyzed. The results demonstrate that defect-free converters can be easily obtained by controlling the layer strain present in the system.

Several photoluminescence and photoreflectance studies are conducted for the characterization of the properties exhibited by the [Zn.sub.x][Cd.sub.1-x]Se/Mg Se multiple quantum wells. The various interband transitions taking place in these structures are also analyzed.

The performance of quantum dot (QD)-sensitized solar cells based on CdSe QD sensitizer on a preadsorbed layer of CdS QDs together with the basic studies of optical absorption and photoelectrochemical current characteristics is described. The photovoltaic conversion efficiency of combined CdS/CdSe QD-sensitized solar cells has displayed a maximum value of 3.5%.

A large reversible magnetocaloric effect (MCE) near the ordering temperature has occurred and the values of the maximum magnetic-entropy change has reached 18.3 J[kg.sup.-1][K.sup.-1] for the field change of 5 T with no hysteresis loss around 17 K. The results have shown that [Er.sub.4]NiCd is a promising system for magnetic refrigeration at temperatures below liquid [H.sub.2].

The new cubic [Cd.sub.1-x][Mn.sub.x]S/GaAs(100) epilayers are grown by hot-wall epitaxy and their structural and optical properties are examined by x-ray diffraction (XRD) and photoluminescence (PL). The studies have shown that in the cubic [Cd.sub.1-x][Mn.sub.x]S epilayers, only yellow emission PL peaks are observed at 2.0 eV without other peaks such as the appreciable near-edge emission peak and self-activated peak

The mechanisms involved in the luminescence enhancement of the CdTe nanostructures in La[F.sub.3]:Ce/CdTenanocomposites are analyzed. Energy transfer, light reabsorption and defect passivation are shown to be some of the main reasons that lead to the observed enhancement.

The impact of the shell thickness on the solar cell performance is understood by examining its effect on interfacial charge separation and recombination kinetics in CdSe/ZnS type I core/shell quantum dots (QDs). The studies have provided different ways of optimizing the charge separation yield and lifetime by controlling the thickness and nature of the shell materials.

Titanium dioxide nanotubes have provided distinct advantages over films of the same material in the production of hydroxyl radicals and subsequent inactivation of Escherichia coli in wastewater. Semiconducting nanocrystals of cadmium sulfide are used to increase the sensitivity of Ti[O.sub.2] nanotubes to visible light and a small applied potential, using CdS-coated Ti[O.sub.2] nanotube arrays, has allowed for the total inactivation of Escherichia coli in record short time.

Highly regular, single-crystalline nanopillar arrays with tunable shapes and geometry are prepared by the template-assisted vapor-liquid-solid growth mechanism. The process is shown to be highly generic for various material systems and CdS and Ge nanopillar arrays are shown with square, rectangular and circular cross section.

An enhanced original computer program is used for describing the current-voltage characteristics of n-on-p long wavelength infrared HgCdTe photodiodes. The studies have explained the impact of Hg-vacancy doping and extrinsic doping of an active device region on dark current-voltage characteristics and an [R.sub.0]A product of HgCdTe photodiodes in a wide region temperature and wavelengths.

Scanning Kelvin probe microscopy (SKPM) is used for examining cross sections of working CdTe/CdS solar cells. The distribution of the potential and electrical field inside a CdTe/Sn[O.sub.2] device, without the CdS layer, is examined and PoissonEs equation is used for estimating the doping inside the CdTe film in both devices.

The optical properties of dissociative luminescent sensors based on a complex consisting of highly luminescent hydrophobic core/shell CdSe/ZnS quantum dots (QDs) and 1-(2-pyridilazo)-2-naphtol (PAN) molecules in organic solutions and a polymer film are studied. [Ni.sup.2+] and [Co.sup.2+] ions are used to show that the QD/PAN sensor can be used in the quantitative luminescent sensing of metal ions in aqueous solutions.

An accurate and generalized method is proposed in terms of the device design, material properties and operation temperature to analyze the effects of position dependence of carrier concentration, electrostatic potential and generation-recombination (g-r) rates on detector performance. The suitability of the method is highlighted by showing the feasibility of achieving the optimum device performance by carefully selecting the device design and other parameters.

The article presents a new geometry of the plasmonic inverse rib optical waveguide for demonstrating tight confinement and smooth interface in the system. The application of the new technology for large scale fabrication of different elements is also analyzed.

The fabrication and characterization of CdS/Ti[O.sub.2] nanotube-array coaxial heterogeneous structures which could find possible potential application in various photocatalytic fields, such as water photocatalytic decomposition and toxic pollutant photocatalytic degradation are reported. The detailed synthesis process and the surface morphology, structure, elemental analysis, and photoelectrochemical properties of the resulting films with the CdS/Ti[O.sub.2] nanotube-array coaxial heterogeneous structure might find use in designing multijuction semiconductor materials for coating of highly structured substrates.

A scheme is described for measuring the thermal conductivity of individual nanowires by using temperature-dependent and microphotoluminescence spectroscopy. The temperature gradient across the nanowire and the length of the suspended segment is obtained for extracting the thermal conductivity of CdS nanowires.

The behavior of point defects in Cd[Ga.sub.2][Se.sub.4], grown by the hot-wall epitaxy method, is examined by measuring photoluminescence (PL) after the postannealing in various ambient. The Ga in Cd[Ge.sub.2][Se.sub.4] has not formed native defects because the Ga is present in the form of stable bonds in Cd[Ga.sub.2][Se.sub.4] and a band diagram of the recombination process in Cd[Ga.sub.2][Se.sub.4] is described.

Optical characterization of two wurtzite ZnCdMgSe crystalline alloys grown by the modified high-pressure Bridgman method is performed by using temperature-dependent photoluminescence (PL) and contactless electroreflectance (CER) in the temperature range of 10-300 K and photoreflectance (PR) measurements between 300-400 K. The parameters describing the temperature dependence of the transition energies and broadening parameters of the band edge excitonic transitions are analyzed.

A combination of scanning electron microscopy and various other techniques is employed to explain the synthesis, characterization and properties of the high-quality CdTe nanowires. These nanowires are shown to be widely applicable for a large number of nanoelectronic and nanophotonic applications.

Several studies are conducted to explain the thermal expansion taking place in the different series of thermoelectric type-I-clathrates. The thermal expansion is shown to be highly dependent on the temperature and the thickness of the clathrates.

Thin films of wurtzite [Mg.sub.x][Zn.sub.1-x]O grown by molecular beam epitaxy and wurtzite [Cd.sub.x][Zn.sub.1-x]O grown by metal organic chemical vapor deposition are implanted at room temperature with [Er.sup.+] ions and [Au.sup.+] ions and damage accumulation is analyzed by Rutherford backscattering/channeling spectrometry. The results have shown that the film composition has affected the damage accumulation behavior in both MgZnO and CdZnO and the increase of Cd content in CdZnO has affected the saturation stage of the damage accumulation, leading to an increase of damage production in both Cd and Zn sublattices.

Solution NMR methods are used for analyzing the organic/inorganic interface of CdSe quantum dots (Q-CdSe) prepared by using oleic acid as a surfactant. The studies have shown that the resulting Q-CdSe is stabilized by tightly bound oleic acid species that only exchange upon addition of free oleic acid.

Different strategies are developed for preparing colloidal nanocrystals stabilized with molecular metal chalcogenide complexes (MCCs). The development of mild synthetic routes is very important for designing highly luminescent all-inorganic nanocrystals, such as CdSe/ZnS and PbS capped with [Sn.sub.2][S.sub.6.sup.4-] MCCs.

The anionic framework of the crystal is preserved even during the replacement of cationic sublattice with a different metal ion via reversible place exchange in ionic nanocrystals. This method has ensured that compositional interfaces within the heterostructure are conserved throughout the transformation when it is applied to nanoheterostructures.

Several pump power dependent infrared measurements are conducted to explain the modulation mechanisms of photoreflectance as exhibited by the infrared photoreflectance in narrow-gap HgCdTe epilayers. The excess carrier concentration of the epilayers is shown to exhibit an extremely significant role in the functioning of these epilayers.