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The processes of electron scattering on a short-range potential caused by interaction with polar and nonpolar optical phonons, piezoelectric and acoustic phonons, static strain, and neutral and ionized impurities in wurtzite n-ZnO with impurity concentration ~1 x [10.sup.17] [cm.sup.-3] are considered. The temperature dependences of electron mobility and Hall factor in the range 15/550 K are calculated. PACS Nos.: 72.10.-d, 72.10.Di, 72.10.Fk. Nous etudions ici la diffusion des electrons dans la wurtzite n-ZnO, par un potentiel a courte portee cause par l'interaction avec des phonons optiques polaires et non polaires, des phonons piezoelectriques et acoustiques, une deformation statique ou des impuretes neutres ou ionisees de concentration ~1 x [10.sup.17] [cm.sup.-3]. Nous calculons la dependance de la mobilite des electrons et du facteur de Hall sur la temperature dans le domaine 15/550 K. [Traduit par la Redaction], 1. Introduction Zinc oxide is a semiconducting material that finds a wide application in device structures; ZnO is very resistive to high-energy radiation making it a very suitable candidate for [...]

The present study was undertaken because ZnO is being used as affinity probes for enhancing the signal intensities of bacterial analytes. Since, ZnO is established for its bactericidal activity, it is vital that the threshold concentrations up to which ZnO does not show bactericidal activity and above which concentration the bactericidal activity of ZnO becomes pronounced is identified. The results showed that at concentrations below 10 g/L, such as 5 and 1 g/L ZnO NPs did not damage the E. coli cells much but improved the intensity of most of the peaks in the spectra. For the first time, this paper reports the use of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) for assessing the damage incurred on the bacterial cells. The results showed significant differences in spectral pattern confirming that MALDI-TOF MS was successful in evaluating the bactericidal activity. This paper is unique in that it presents the results of the comparative study conducted in assessing the capability of MALDI-TOF MS with the existing conventional plating technique which is generally used to estimate bactericidal activity. This study brings out the inadequacy of the conventional plating techniques used in microbiology to depict antibacterial activity. On the other hand, MALDI-MS analysis led to direct, simple, and rapid acquisition of data (5 min for each measurement) which promptly reflected the bactericidal activity. 10.1021/ac102255y

The efficacy of an inactive [Al.sub.2][O.sub.3] layer deposited between a polymer and a ceramic surface layer to minimize photocatalytic oxidation is determined by evaluating the photochemical behaviors of various ceramic/polymer systems subjected to accelerated photoaging conditions. The results have shown that although irradiation increased the nanohardness and the elastic modulus of polycarbonate (PC), the irradiation effect on the surface mechanical properties of ceramic-coated PC was secondary.

ZnO nanoneedle arrays are grown on a large scale with a chemical vapor deposition method at 680 degree Celsius and Zn powder and O2 gas and are employed as source materials and catalyst-free Si plates are used as substrates. Field-emission examination exhibits that the ZnO nanoneedle arrays have a turn-on voltage at about 5.3 V/mum.

The current-dependent morphology evolution and photoluminescence properties of zinc oxide (ZnO) films prepared by electrochemical (ECD) method are studied. All the ZnO films prepared over a wide current range show strong ultraviolet (UV) emission at room temperature, which also shows deposition current dependence in intensity, together with relatively weak defect-related green emission under UV excitations.

Photoluminescence and positron annihilation spectroscopy are used to characterize and identify vacancy-type defects produced in ZnO films grown on sapphire by metal-organic chemical-vapor deposition. The found relation between the intensity of the photoluminescence spectra and Zn vacancy concentration indicates that the 370.5nm (3.346 eV) emission line is related to the presence of Zn vacancies.

The band structures of wurtzite ZnO are calculated by the empirical pseudopotential method (EPM). The eight parameters of the Zn and O atomic preudopotential form factors are obtained.

A study to demonstrate the incorporation of metallic dopants in ZnO nanowires in the low-temperature process was conducted. This fast growth technique provided a route to fabrication of low-cost highly oriented ZnO nanowire on polished substrate for industrial applications.

Stimulated emission was studied using time-integrated and time-resolved photoluminescence in ZnO comb, tetrapod, and rod nanostructures. The nanostructures were fabricated by vapor deposition and hydrothermal methods.

(Mn, Co)-codoped ZnO films are synthesized on c-sapphire (001) by a radio-frequency magnetron sputtering system in which two targets are sputtered together. X-ray diffraction measurements indicate that the films are highly c-axis oriented.

A study reports about the room-temperature ultraviolet stimulated emission and lasing from optically pumped high-quality ZnO nanowires. Details of the characteristic cavity length that is determined by the Fourier transform of the lasing spectrum are discussed.

A study was carried out on the phosphorus ion that were implanted in ZnO single crystals with energies of 50-380 keV having total doses of 4.2*10(super 13) -4.2*10(super 15) cm(super -2). The study showed that the phosphorus is an amphoteric dopant as the Hall measurement indicates an n-type conductivity for the P(super +) implanted ZnO layer.

A hybrid OM/MM embedding model within the computational chemistry package ChemShell is applied, to study in detail the interaction of copper atoms and clusters in various, potentially important catalytic oxidation states (Cu, Cu+, and Cu2+) on polar surfaces. The model is applied to copper atoms, ions and clusters (Cu sub n, n=1,4) on the zinc-terminated (0001) surface of ZnO.

Near-IR absorption spectra of electrons injected from excited sensitizer dyes to nanocrystalline ZnO films are studied. The absorption steeply increases with increasing wavelength and can be assigned to the optical transition of conducting electrons to higher energy levels of the conduction band.

The charge transport in nanoparticulate ZnO layers held at different potentials is studied by analyzing the anodic transient photocurrents. The results reveal that the effective diffusion constant for the electron transport through ZnO film held at positive potentials is calculated to be 1.7 x 10(super -4) cm(super 2)/s which is in good agreement with diffusion constants.

Anion exchange with S is performed on ZnO colloidal nanoparticles and the resulting hollow ZnS nanoparticles are crystal whose shape is dictated by the initial ZnO. Crystallographic and elemental analyses have helped in understanding the mechanism of the anion exchange.

The dielectric properties of [Cu.sub.0.5]T[I.sub.0.5][Ba.sub.2][Ca.sub.2][Cu.sub.3-y][Zn.sub.y][O.sub.10-[delta]] (y=0, 1.0, 1.5, 2.0, 2.5) superconductors are analyzed in order to examine the effects of Zn atoms and their role in modifying dielectric properties. The studies have helped in understanding the role of carriers concentration in the conducting Cu[O.sub.2]/Zn[O.sub.2] planes and have also shown that the role of mobile carriers in the conducting planes is needed in determining certain values of capacitance.

In-phase and out-of-phase textured ZnO films are examined by using ion-beam-assisted electron-beam evaporation in order to determine the effect of ion irradiation on the (1010) texture formation. The analysis has shown the potential of an in-plane texture-controlled ZnO film for use in shear mode piezoelectric devices.

An electron paramagnetic resonance (EPR) is used to study the photoinduced changes in charge states of transition-metal impurities in a hydrothermally grown ZnO crystal. The results have shown that the isolated zinc vacancies and oxygen vacancies are not present in measurable concentrations in as-grown hydrothermal crystals.

The electronic structure of the Co substituted ZnO thin films are studied by using low temperature photoluminescence (PL) measurements and ultraviolet (UV)-visible absorption spectroscopy. The Co-doped ZnO films have shown three sharp levels and two shoulder levels of crystal field splitted Co d orbitals, respectively.

The variations of the optical, structural and electrical properties of [Zn.sub.1-x][Mg.sub.x]O thin films are investigated with respect to substrate temperature variations and postannealing. The results have shown that the properties of [Zn.sub.1-x][Mg.sub.x]O thin films depend on substrate temperatures and the postannealing treatment with changes in the Mg composition.

An effective, low cost simple, and mask-free pathway is demonstrated for achieving density control of the aligned ZnO nanowires grown for large-scale applications. The study represents an approach for growing aligned nanowire arrays on a ceramic substrate with the simultaneous formation of a continuous conducting electrode at the roots, which is important for device applications, such as field emission.

The morphology of Cu films deposited on polar (0001)-Zn and (0001)-O surfaces of ZnO at room temperature is investigated with STM. The analysis done through three dimensional cluster growth mode showing a strong dependence of Cu growth on surface defects is observed.

Electron paramagnetic resonance (EPR) is used to investigate molecular nitrogen and isolated nitrogen acceptors in single crystals of ZnO. These samples when grown by the seeded chemical vapor transport method with N2 added to the gas stream, arise from nearly equal hyperfine interactions with two nitrogen nuclei.