Abstract:
Nanowhiskers are grown in a non-preferential growth direction by regulation of nucleation conditions to inhibit growth in a preferential direction. In a preferred implementation, III-V semiconductor nanowhiskers are grown on an (001) III-V semiconductor substrate surface by effectively inhibiting growth in the preferential B direction. As one example, InP nano-wires were grown by metal-organic vapor phase epitaxy directly on (001) InP substrates. Characterization by scanning electron microscopy and transmission electron microscopy revealed wires with nearly square cross sections and a perfect zincblende crystalline structure that is free of stacking faults.
Abstract:
In a method of making an elongated carbide nanostructure, a plurality of spatially-separated catalyst particles is applied to a substrate. The spatially-separated catalyst particles and at least a portion of the substrate are exposed to a metal-containing vapor at a preselected temperature and for a period sufficient to cause an inorganic nanostructure to form between the substrate and at least one of the catalyst particles. The inorganic nano-structure is exposed to a carbon-containing vapor source at a preselected temperature and for a period sufficient to carburize the inorganic nanostructure.
Abstract:
Nanostructures (18) and methods for production thereof by phase separation during metal organic vapor-phase epitaxy (MOVPE). An embodiment of one of the methods may comprise providing a growth surface in a reaction chamber and introducing a first mixture of precursor materials into the reaction chamber to form a buffer layer (12) thereon. A second mixture of precursor materials may be provided into the reaction chamber to form an active region (14) on the buffer layer (12), wherein the nanostructure (18) is embedded in a matrix (16) in the active region (14). Additional steps are also disclosed for preparing the nanostructure (18) product for various applications.
Abstract:
AFM/STM probes are based on whiskers grown by the vapor-liquid-solid (VLS) mechanism. Silicon cantilevers oriented along the crystallographic plane (111) are prepared from silicon-on-insulator structures that contain a thin layer (111) on a (100) substrate with SiO2 interposed layer. At removal of solidified alloy globules inherent in the growth mechanism sharpening of the whiskers takes place and, in such a way, the probes are formed. Cross-sections of the wiskers grown by the mechanism on the cantilevers can be controllably changed during the growth process so that step-shaped whiskers optimal for fabrication of the probes can be prepared. Also, whiskers with expansions/contractions can be formed that are important for fabrication of probes suitable for investigations in coarse surfaces, complicated cavitites, grooves typical for semiconductor microelectronics, etc.