Carbon Nanotube


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Revolution in microelectronics can exercise monookis carbon (carbon monoxide) - toxic substances, called smoke inhalation. CO molecules in the presence of iron catalyst at a sufficiently high temperature molecules form a hexagon of carbon atoms, which then formed an orderly film, which creates seamless cylinders - nanotubes. While they may contain millions of atoms, their size does not exceed the size of the point at the end of this sentence. Nevertheless nanotubes - a single molecule. A more robust than steel, the construction simultaneously combines the properties of copper and silicon.

Carbon nanotubes (single-walled carbon nanotubes - SWNT) were discovered in 1991 by Sumio Iijima (firm NEC, Japan). It was later discovered that the data are ambiguous nature of education: they can behave as companions or as semiwires (become agents of tension when submitting certain value), subject to tighten molecules into a spiral. This dualism - the perfect combination of elements to create a computer engineering nano-sized. Geometric combination nanotubes showed identity of their properties diodes, transistors, the key elements and other components of the current silicon technology.

A simple and effective solution was the use of a rectangular grid nanotubes simultaneously as a matrix of memory and I / O devices. This structure provides a bi-stable condition electrostatically switch in each intersection of the grid nanotubes. Detailed analysis showed that the strength of elasticity occurred at a time when the upper nanotubes maximum removed from the bottom, and Van der Waals forces arising from the convergence of their tubes at the point of intersection, determine two pronounced power of the state memory cell. In the first transitional state of resistance between nanotubes great, the second condition - short. By providing electrically attracted and repulsive force between nanotubes, you can enter data. Because electrostatic effect is applied only to specific end nanotubes, rather than to each memory cell, the problem compounds "macroworld" and "microworld" largely resolved.

The problem is defined orientation nanotubes and their connection. This is achieved by a chemical so that the nanotubes are fixed chemical "tag", which are necessary in self-nanotube structures. This process is called "selective functionalization". Tags attract or discourage the ends of nanowires and nanosemiwires, creating a functional chain. However, some scientists believed that the decision not under such a task force of modern chemistry. They believe that enough to start at least supplement the existing limit silicon technology based on nanotechnology nanotubes.

There are other possible application of nanotubes. Samsung and Lucent Technologies proposes to use them in the ultra television displays, as shields electromagnetic radiation in tubes cellular communications and portable computers. Given the high strength tubes (100 times greater than steel) offers a number of researchers to use them for the execution of dreams Arthur C. Clarke - compounds satellites in geostationary orbit with Earth-cable.

Thus, nanotubes may themselves be material to create a microelectronic technology components, furthermore, as companions, they can potentially provide telecommunications molecular devices with the "outside world". However, most existing thin "thick wire macroworld" have a diameter of about 200 nanometers, and the thickness of nanotubes is only about two nanometers, which corresponds to ten atoms of carbon.

Researchers from Hewlett-Packard to suggest the establishment of such compounds with the help of an accidental chemical process with the subsequent selection of the right connections. The border contact macro and microwire "sown" particles of gold. Experimentally determined that the optimal concentration of particles of gold provides a 50% probability of connections "microscopic" wire with a "macroscopic". Random set of relationships with agents of the macro and microwire can be defined as a code word defining the unique address nanowire. Ideally, for adresovaniya thousands nanowires must be makroprovodov hundred (210 = 1024), but addresses duplicated and effective adresovanie significantly worse.

Using more macrowires corrects the situation (that is consistent with the theory of coding). Hewlett-Packard Specialists believe that the increase in the number macrowires well uchetverennomu logarithm of nanowires (the apparently experimental data have confirmed).

To determine all unique addresses a special algorithm that uses measurements of resistance compounds nano- and macro-wires.