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F L Deepak

Publications and source records attributed to F L Deepak.

3 recordsLinked to original sources

Pressure-induced structural phase transformations in silicon nanowires.

High-pressure structural behavior of silicon nanowires is investigated up to approximately 22 GPa using angle dispersive X-ray diffraction measurements. Silicon nanowires transform from the cubic to the beta-tin phase at 7.5-10.5 GPa, to the Imma phase at approximately 14 GPa, and to the primitive hexagonal structure at approximately 16.2 GPa. On complete release of pressure, it transforms to the metastable R8 phase. The observed sequence of phase transitions is the same as that of bulk silicon. Though the X-ray diffraction experiments do not reveal any size effect, the pressure dependence of Raman modes shows that the behavior of nanowires is in between that of the bulk crystal and porous Si.

Crystallization↗

Single crystal GaN nanowires.

Single crystal gallium nitride nanowires have been obtained by heating gallium acetylacetonate in the presence of carbon nanotubes or activated carbon in NH3 vapor at 910 degrees C. GaN nanowires also were obtained when the reaction of gallium acetylacetonate with NH3 was carried out over catalytic Fe/Ni particles dispersed over silica. The former procedure with carbon nanotubes is preferable because it avoids the presence of metal particles in the nanowire bundles.

Ammonia↗