Buckyballs: C-60 to Flash Memory

Buckyballs were discovered in 1985 - the product of an experiment on carbon molecules in space. However, it was not until 1991 that buckyball science came into its own. Just how do buckyballs manage their chemical and physical feats? In C60, hexagons and pentagons of carbon link together in a coordinated fashion to form a hollow, geodesic dome with bonding strains equidistributed among 60 carbon atoms. Some of the electrons are delocalized over the entire molecule--a feature even more pronounced in that workhorse of organic chemistry, benzene. Benzene is flat and many of its derivatives also tend to stack in flatsheets. Spherical buckyballs literally add a new dimension to the chemistry of such aromatic compounds. Buckministerfullerine has been named the Molecule of the Year. In addition to opening up new fields on chemistry, C60 also shows interesting physical properties. It is resistant to shock and it has been suggested that as a lubricant, there is even evidence of superconductivity and it may provide the added ingredient that makes diamond films more practical.

Until a few years ago, there were two known forms of pure carbon, graphite and diamond. Then an improbable-seeming third form of carbon was discovered: a hollow cluster of 60 carbon atoms shaped like a soccer ball. Buckminsterfullerene or "buckyballs"--named for the American architect R. Buckminster Fuller, whose geodesic domes had a similar structure--is the roundest, most symmetrical large molecule known. It is exceedingly rugged and very stable, capable of surviving the temperature extremes of outer space. At first, however, the molecule was a mystery wrapped in an enigma. But when a convenient way of making this molecule, also known as C60, was discovered, it set off an explosion of research among chemists, physicists, and materials scientists to uncover the molecule's secrets. Investigators soon discovered a whole family of related molecules, including C70, C84 and other "fullerenes"--clusters as small as C28 and as large as a postulated C240.These unusual molecules turn out to have extraordinary chemical and physical properties.They react with elements from across the periodic table and with the chemical species known as free radicals--key to the polymerization processes widely used in industry--thus opening up the fullerenes to the manipulative magic of organic chemists. When a fullerene is "doped" by inserting just the right amount of potassium or cesium into empty spaces within the crystal, it becomes a superconductor--the best organic superconductor known.

The use of buckyballs in industry became the topic of discussion.With the growing technology and the want for a faster communicating medium,the bucky ball made its way to digital electronics. The flash memory was enhanced by the use of C60 in it. Flash memory consist of a transistor which has a gate ,drain and a source. The gate is separated from the transistor by a layer of insulation,the gate dielectric. The gate contains another ‘floating gate’ in the embedded dielectric. By varying the voltage on the gate the charge can be made to enter or leave the inner gate. The presence or absence of charge at the floating gate denotes the present bit. The flash memories have many such transistors and have followed the Moore’s law for years, but the power consumption is also high. The flash require about 11V-13V of supply for entering the charge or removing it from the dielectric. If the dielectric is made thinner then the charge can move faster but it may also result in leaking of charge. Buckyballs are now used to provide a path for charge to enter the dielectric and leave it faster. They are like the stepping stones in a river to cross from one side to another. Enough potential difference can cause them to show up and then the charge transfer can take place without disturbing the dielectric dynamics. This can enhance the speed of flash memories and bring down the power supply from 13V to 5V.

The cost of flash memories may increase due to it but may also be a very handy weapon to enervate the power consumption. Use of such technologies in DRAM’s can also prove to be effective.

More information on use of buckyballs through your comments would be appreciated.

GRAPHENE:The Faster Substitute

When we all had imagined that the Moore's law will hold good for more than 40 odd years, Silicon,the king of semiconductor materials just got a substitute. The industry which is gaining great impetus and leverage over the growth of Si market, is experimenting for the faster semiconductor. Which, in turn, gives faster speed to the digital circuitry. The fact lies that the major masses of the world(i.e. INDIANS) just discovered the computer as a essential commodity a few years ago. The world digital industry is trying to fulfill the dream of the faster machine by giving in to different Processors and RAM's(an average Indian can relate speed of the computer to only these two things), industry modified silicon substrates to give us a better machine. Now, comes in the hero of the evening, Graphene; Graphene is the atomic particulate which can be obtained graphite(the pencil lead). The smudge of the pencil, is that of graphene. It has a one atom thick crystal with great electric properties. Experiment conducted in Maryland University state that when at room temperature, electrons travel at 200,000cm/sec in 1V/cm electric field. This is 100 times faster than the normal movement of electron in Si, hence a faster material for conduction. The smallest transistor was made from graphene which was to be 1 atom thick and 10 to 50 atoms wide. It is not a natural choice of transistor material as it does not have a electric bandgap i.e. the graphene transistor is hard to turn off. Andre Geim & Kostya Novoselov of the Manchester University overcame the obstacles by etching off some of the Graphene to create narrow constrictions which provided the bandgap.
The speed of electron transfer due to graphene has got the world excited & its research is getting funded from right across Europe to USA. Graphene can relatively reduce the chip size and reduce the magnanimity of heavy RF circuits. Its high conductance can be used to pack in more power in batteries and to make more sensitive sensors. An expert in 2D dynamics of an electron from Harvard University has said that graphene may not be able to replace Si completely but would surely take a large chunk of its industry for its own. he further says that due to graphene all the rules about how the electron behaves are changed.
The topic is hot to handle but too precious to be missed hence please post comments if you all find some interesting reports in this field. Very fast it is but is it reliable is the question. Small it is to the big daddy Silicon but David did beat Goliath, didn't he?
More on topic at http://www.spectrum.ieee.org

Photon transistor

Researchers dream of quantum computers. Incredibly fast super computers which can solve such extremely complicated tasks that it will revolutionise the application possibilities. But there are some serious difficulties. One of them is the transistors, which are the systems that process the signals.
Today the signal is an electrical current. For a quantum computer the signal can be an optical one, and it works using a single photon which is the smallest component of light.
"To work, the photons have to meet and "talk", and the photons very rarely interact together" says Anders Søndberg Sørensen who is a Quantum Physicist at the Niels Bohr Institute at Copenhagen University. He explains that light does not function like in Star Wars, where the people fight with light sabres and can cross swords with the light. That is pure fiction and can't happen. When two rays of light meet and cross, the two lights go right through each other. That is called linear optics.
What he wants to do with the light is non-linear optics. That means that the photons in the light collide with each other and can affect each other. This is very difficult to do in practice. Photons are so small that one could never hit one with the other. Unless one can control them -- and it is this Anders Sørensen has developed a theory about.

The submissive power of the photon does not allow it interact with other photons.The process by which a photo can be made to interact with the other is by the use of nano wires.

Nano wires being smaller than the optic fibre can be used effectively for this purpose.

1. the red photon can be made to enter the nano wire from one end and green photon from other end.

2. An atom of a heavy element can behave as a force provider the divert the photos from their respective paths.

3.On collision, the photon with with a larger phase will be able to carry some energy of the other photon (i.e. the green one in the example carries the energy of the red photon). this is the principle of signal processing revisited .

This idea was concieved at the Copenhagen University and is currently being researched at many universities including Harvard.

(ref: IEEE Spectrum July 2008;

Detailed work by Anders Sørensen)

Your ideas are welcome on this topic & plz post any new innovations in the industry.