Tungsten oxide nanowire synthesis from amorphous-like tungsten films.

A synthesis technique which can lead to direct integration of tungsten oxide nanowires onto silicon chips is essential for preparing various devices. The conversion of amorphous tungsten films deposited on silicon chips by pulsed layer deposition to nanowires by annealing is an apt method in that direction. This perspective discusses the ingenious features of the technique reported by Dellasega et al on the various aspects of tungsten oxide nanowire synthesis.

Carbon-nanotube-embedded novel three-Dimensional alumina microchannel cold cathodes for high electron emission.

The present work describes a comprehensive design and scalable micro-fabrication technique for the production of novel 3D cathodes, consisting of chemical-vapor-deposition-grown high-density multi-wall carbon nanotubes along the walls of alumina microchannels. Under high DC and AC electric fields, the 3D cathodes displayed significantly high and moderately stable emission current of approximately 5.25 and approximately 14 mA, respectively. The inherent advantages of the 3D microchannel geometry for cold cathodes are higher emitter area, less ion bombardment and robustness under high voltage conditions. The 3D cathodes are envisioned to offer an entirely new class of miniature electron sources for high current vacuum microelectronics.

Enhanced field emission from aligned multistage carbon nanotube emitter arrays.

In this work we report on the synthesis and field emission properties of carbon nanotube multistage emitter arrays grown on porous silicon by catalytic thermal chemical vapor deposition. The vertically oriented multistage array structures consisted of SWNTs and thin MWNTs grown on MWNTs, confirmed by TEM and Raman analysis. Higher field emission current ∼32 times and low threshold field ∼1.5 times were obtained for these structures in comparison to only MWNT arrays. The enhanced field emission results for these multistage emitters are a consequence of higher field concentration, which is ∼3 times more than MWNTs.

Recent progress of carbon nanotube field emitters and their application.

The potential of utilizing carbon nanotube field emission properties is an attractive feature for future vacuum electronic devices including: high power microwave, miniature x-ray, backlight for liquid crystal displays and flat panel displays. Their high emission current, nano scale geometry, chemical inertness and low threshold voltage for emission are attractive features for the field emission applications. In this paper we review the recent developments of carbon nanotube field emitters and their device applications. We also discuss the latest results on field emission current amplification achieved with an electron multiplier microchannel plate, and emission performance of multistage field emitter based on oxide nanowire operated in poor vacuum.

Lattice dynamics of MgO at high pressure: theory and experiment.

The longitudinal acoustic and optical phonon branches along the Gamma-X direction of MgO at 35 GPa have been determined by inelastic x-ray scattering using synchrotron radiation and a diamond-anvil cell. The experimentally observed phonon branches are in remarkable agreement with ab initio lattice dynamics results. The derived thermodynamic properties, such as the specific heat CV and the entropy S are in very good accord with values obtained from a thermodynamically assessed data set involving measured data on molar volume, heat capacity at constant pressure, bulk modulus and thermal expansion.