In this study, we comparatively analyzed the physical properties of Hg2Br2 and Hg2BrxCl2−x crystals synthesized via physical vapor transport (PVT). Prior to crystal growth, the elemental mapping images obtained through scanning electron microscopy/energy-dispersive spectroscopy clearly showed the presence of Cl atoms (2.62%) in Hg2BrxCl2−x powder; however, Cl atoms were not detected in Hg2Br2 powder. After crystal growth by PVT, each single crystal was characterized using various analysis techniques, such as X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. It was observed that the introduction of Cl elements into Hg2Br2 crystals strongly affected the crystallinity and Raman vibration modes. Hence, this in-depth material characterization study proposed a feasible method to screen impurities in mercury halide crystals.
Sol‐gel approach to magnesium oxide has been utilized for the fabrication of its protective thin films of Plasma Display Panel (PDP) dielectrics. The MgO films derived from the solution reproducibly present good crystallinity and surface morphology. The solution was coated on large size PDP and calcined at about 480 °C in air to obtain high quality NlgO thin film. The PDP thus obtained at a lower producing cost showed similar electrical properties for practical applications compared with electron beam evaporated one.
Abstract:We have grown GaN nanowires by the low pressure MOCVD method on Ni deposited oxidized Si surface and have established optimum conditions by observing surface microstructure and its photoluminescence. Optimum growth temperature of 880℃, growth time of 30 min, TMG source flow rate of 10 sccm have resulted in dense nanowires on the surface, however further increase of growth time or TMG flow rate has not increased the length of nanowire but has formed nanocrystals. On the contrary, the increase of ammonia flow has increased the length of nanowires and the coverage of nanowire over the surface. The shape of nanowire is needle-like with a Ni droplet at its tip; the length is tens of micron with more than 40 nm in diameter. Low temperature photoluminescence obtained from the sample at optimum growth condition has revealed several peaks related to exciton decay near band-edge, but does not show any characteristic originated from one dimensional quantum confinement. Strong and broad luminescence at 2.2 eV is observed from dense nanowire samples and this suggests that the broad band is related to e-h recombination at the surface state in a nanowire. The current result is implemented to the nanowire device fabrication by nanowire bridging between micro-patterned neighboring Ni catalysis islands.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.