Heterojunction and superlattice formation is essential for many potential applications of semiconductor nanowires in nanoscale optoelectronics. We have developed a hybrid pulsed laser ablation/chemical capor deposition (PLA-CVD) process for the synthesis of semiconductor nanowires with longitudinal ordered heterostructures. The laser ablation process generates a programmable pulsed vapor source, which enables the nanowire growth in a block-by-block fashion with a well-defined compositional profile along the wire axis. Single-crystalline nanowires with longitudinal Si/SiGe superlattice structure have been successfully synthesized. This unique class of heterostructured one-dimensional nanostructures holds great potential in applications such as light emitting devices and thermoelectrics.

http://web.eng.fiu.edu/wangc/block by block growth of single crystalline si sige superlattice nanowires.pdf

Block-by-Block Growth of Single-Crystalline Si/SiGe Superlattice Nanowires

A review. C nanotubes are one of the most intensively explored nanostructured materials. In particular, C nanotubes are unique and ideal templates onto which to immobilize nanoparticles allowing the construction of designed nanoarchitectures that are extremely attractive as supports for heterogeneous catalysts, for use in fuel cells, and in related technologies that exploit the inherent smallness and hollow characteristics of the nanoparticles. Here we overview the recent developments in this area by exploring the various techniques in which nanotubes can be functionalized with metals and other nanoparticles and explore the diverse applications of the resulting materials. [on SciFinder(R)]

Metal nanoparticles and related materials supported on carbon nanotubes: methods and applications.

Carbon nanotubes have attracted the fancy of many scientists worldwide. The small dimensions, strength and the remarkable physical properties of these structures make them a very unique material with a whole range of promising applications. In this review we describe some of the important materials science applications of carbon nanotubes. Specifically we discuss the electronic and electrochemical applications of nanotubes, nanotubes as mechanical reinforcements in high performance composites, nanotube-based field emitters, and their use as nanoprobes in metrology and biological and chemical investigations, and as templates for the creation of other nanostructures. Electronic properties and device applications of nanotubes are treated elsewhere in the book. The challenges that ensue in realizing some of these applications are also discussed from the point of view of manufacturing, processing, and cost considerations.

Applications of Carbon Nanotubes

One-dimensional nanostructures having uniform diameters of less than approximately 200 nm. These inventive nanostructures, which we refer to as “nanowires”, include single-crystalline homostructures as well as heterostructures of at least two single-crystalline materials having different chemical compositions. Because single-crystalline materials are used to form the heterostructure, the resultant heterostructure will be single-crystalline as well. The nanowire heterostructures are generally based on a semiconducting wire wherein the doping and composition are controlled in either the longitudinal or radial directions, or in both directions, to yield a wire that comprises different materials. Examples of resulting nanowire heterostructures include a longitudinal heterostructure nanowire (LOHN) and a coaxial heterostructure nanowire (COHN).

Methods of fabricating nanostructures and nanowires and devices fabricated therefrom

This paper focuses on approaches to continuing CMOS scaling by introducing new device structures and new materials. Starting from an analysis of the sources of improvements in device performance, we present technology options for achieving these performance enhancements. These options include high-dielectric-constant (high-k) gate dielectric, metal gate electrode, double-gate FET, and strained-silicon FET. Nanotechnology is examined in the context of continuing the progress in electronic systems enabled by silicon microelectronics technology. The carbon nanotube field-effect transistor is examined as an example of the evaluation process required to identify suitable nanotechnologies for such purposes.

Beyond the conventional transistor

A method based on a controlled solid-solid reaction was used to fabricate heterostructures between single-walled carbon nanotubes (SWCNTs) and nanorods or particles of silicon carbide and transition metal carbides. Characterization by high-resolution transmission electron microscopy and electron diffraction indicates that the heterostructures have well-defined crystalline interfaces. The SWCNT/carbide interface, with a nanometer-scale area defined by the cross section of a SWCNT bundle or of a single nanotube, represents the smallest heterojunction that can be achieved using carbon nanotubes, and it can be expected to play an important role in the future fabrication of hybrid nanodevices.

https://science.sciencemag.org/content/sci/285/5434/1719.full.pdf

E. Landree

Papers

Heterostructures of Single-Walled Carbon Nanotubes and Carbide Nanorods

Heterostructures of Single-Walled Carbon Nanotubes and Carbide Nanorods.