Isotope Junctions Created in Carbon Nanotubes for Spintronic Applications

This invention relates to nanotube (NT) growth of carbon and other materials using an ion implantation process, and more particular to the growth of nanotubes with a specified isotope composition using a selection filter and catalytic transmembrane. An ion source(s) is configured to generate ions from one or more elements including a plurality of different isotopes or unique molecular combinations of two or more different isotopes from at least one of the selected elements. A selection filter(s) directs a subset of the ions onto a catalytic transmembrane to grow nanotubes of a specific isotope composition on the opposite side of the transmembrane. The nanotubes may be uniformly or selectively doped with dopant atoms. A controller can configure the selection filter(s) to sequentially pass different subsets of ions to form isotope, molecular or element junctions in the growing nanotubes.

Background:

Carbon nanotubes (CNTs) have stimulated a great deal of interest in the microelectronic and other industries because of their unique properties including tensile strengths above 35 GPa, elastic modulus reaching 1 TPa, higher thermal conductivity than diamond, ability to carry 1000x the current of copper, densities below 1.3 g/cm3 and high chemical, thermal and radiation stability. CNTs have great promise for devices such as field effect transistors, field emission displays, single electron transistors in the microelectronic industry, and uses in other industries. Commercialization of CNTs will depend in large part on the ability to grow and network CNTs on a large cost-effective scale without compromising these properties.
 

Advantages:

• Provides the means to grow nanotubes having a specified isotope composition from one or more elements doped or undoped at very high purity levels with spatial definition to realize nanotube structures that researches have only simulated and structures and devises not yet envisioned.

Applications:

• Conduits with long coherence lengths at room temperature
• Spin storage registers with long half-lives
• Semi-conductors that operate at a tetra-hertz range, which is three times faster than the state of the art silicon based semi-conductor

Status: issued U.S. patent #8,252,115