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ZnO nanostructures were grown on Aucoated Si 100 substrates by carbonthermal reduction method with the help of Ar at the beginning of growth. The structural and optical properties of ZnO nanostructures strongly depended on the supply time of Ar. When the given time of Ar gas current was 90s, sample was ZnO nanowires with hexagonal morphology. The Raman spectroscopy revealed the low level of oxygen vacancies and Zn interstitials in samples. Room temperature photoluminescence PL spectra exhibited the intensity of green emission increased on the condition of rich oxygen decrease given time of Ar and the nanowire had strongest intensity of UV emission compared with other nanostructures. Green emission is ascribed to the electron transition from the bottom of the conduction band to the antisite defect OZnlevel. © 2008 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim [ABSTRACT FROM AUTHOR]

Anode striations and wall charges, common phenomena in the plasma display panel (PDP) discharge process, are investigated by simulations in both alternating current coplanar and novel shadow mask PDPs. The formation process of striations is presented and the formation mechanism is investigated. The results reveal that in both structures there is an obvious correspondence between the striation distribution and both the negative and the positive charge accumulation on the dielectric layer above the anode. Each of the two contributions to the total wall charge reaches its peak at the positions where the striations emerge. The total wall charge distribution on the other hand, which is the sum of the wall charge collected from electrons and ions, does not show any striation effect at all. [ABSTRACT FROM AUTHOR]

Wellfaceted hexagonal ZnO nanorods have been synthesized by a simple hydrothermal method at relative low temperature 90°C without any catalysts or templates. Zinc oxide ZnO nanorods were grown in an aqueous solution that contained Zinc chloride ZnCl2, Aldrich, purity 98 and ammonia 25. Most of the ZnO nanorods show the perfect hexagonal cross section and wellfaceted top and side surfaces. The diameter of ZnO nanorods decreased with the reaction time prolonging. The samples have been characterized by Xray powder diffraction XRD and scanning electron microscopy SEM measurement. XRD pattern confirmed that the asprepared ZnO was the singlephase wurtzite structure formation. SEM results showed that the samples were rod textures. The surfacerelated optical properties have been investigated by photoluminescence PL spectrum and Raman spectrum. Photoluminescence measurements showed each spectrum consists of a weak band ultraviolet UV band and a relatively broad visible light emission peak for the samples grown at different time. It has been found that the green emission in Raman measurement may be related to surface states. © 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim [ABSTRACT FROM AUTHOR]

We prepared Codoped ZnO films by the electrochemical deposition. Xray diffraction XRD, high resolution transmission microscopy HRTEM, xray photoelectron spectroscopy XPS, atomic force microscope AFM, xray absorption nearedge structure XANES, vibrating sample magnetometer VSM, optical absorption, and photoluminescence PL measurements were carried out on the samples. The results showed Co atoms substituted Zn atoms in the ZnO lattice without the formation of the impurity phase. VSM measurements showed the ferromagnetic properties for the Codoped ZnO samples. When the Co doping concentration increased, the band gaps were widened and the PL peak positions shifted towards the short wavelength direction. © 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim [ABSTRACT FROM AUTHOR]

Zinc oxide (ZnO), with its excellent luminescent properties and the ease of growth of its nanostructures, holds promise for the development of photonic devices. The recent advances in growth of ZnO nanorods are discussed. Results from both low temperature and high temperature growth approaches are presented. The techniques which are presented include metal-organic chemical vapour deposition (MOCVD), vapour phase epitaxy (VPE), pulse laser deposition (PLD), vapour-liquid-solid (VLS), aqueous chemical growth (ACG) and finally the electrodeposition technique as an example of a selective growth approach. Results from structural as well as optical properties of a variety of ZnO nanorods are shown and analysed using different techniques, including high resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), photoluminescence (PL) and cathodoluminescence (CL), for both room temperature and for low temperature performance. These results indicate that the grown ZnO nanorods possess reproducible and interesting optical properties. Results on obtaining p-type doping in ZnO micro- and nanorods are also demonstrated using PLD. Three independent indications were found for p-type conducting, phosphorus-doped ZnO nanorods: first, acceptor-related CL peaks, second, opposite transfer characteristics of back-gate field effect transistors using undoped and phosphorus doped wire channels, and finally, rectifying I-V characteristics of ZnO:P nanowire/ZnO:Ga p-n junctions. Then light emitting diodes (LEDs) based on n-ZnO nanorods combined with different technologies (hybrid technologies) are suggested and the recent electrical, as well as electro-optical, characteristics of these LEDs are shown and discussed. The hybrid LEDs reviewed and discussed here are mainly presented for two groups: those based on n-ZnO nanorods and p-type crystalline substrates, and those based on n-ZnO nanorods and p-type amorphous substrates. Promising electroluminescence characteristics aimed at the development of white LEDs are demonstrated. Although some of the presented LEDs show visible emission for applied biases in excess of 10 V, optimized structures are expected to provide the same emission at much lower voltage. Finally, lasing from ZnO nanorods is briefly reviewed. An example of a recent whispering gallery mode (WGM) lasing from ZnO is demonstrated as a way to enhance the stimulated emission from small size structures. [ABSTRACT FROM AUTHOR]