Molecular transistors

[wigglieverse]

"(Nanowerk Spotlight) Transistors are the fundamental building blocks of our everyday modern electronics; they are the tiny switches that process the ones and zeroes that make up our digital world. Transistors control the flow of electricity by switching current on or off and by amplifying electrical signals in the circuitry that governs the operation of our computers, cellular phones, iPods and any other electronic device you can think of. The first transistor used in commercial applications was in the Regency TR-1 transistor radio, which went on sale in 1954 for $49.95, that's over $375 in today's dollars ...While the first transistors were over 1 centimeter in diameter, the smallest transistors today are just 30 nanometers thick - three million times smaller.

 

This feat would be equivalent to shrinking the 509-meter tall Taipei 101 Tower, currently the tallest building in the world, to the size of a 1.6 millimeter tall grain of rice. The 32nm microprocessor Intel plans to introduce in 2009 will pack a whopping 1.9 billion transistors. However, current microprocessor technology is quickly approaching a physical barrier. Switching the current by raising and lowering the electron energy barrier generates heat, which becomes a huge problem as device densities approach the atomic limit. An intriguing - and technologically daunting - alternative would be to exploit the wave nature of the electron, rather than its particle properties, to control current flow on the nanoscale. Such a device, called the Quantum Interference Effect Transistor (QuIET), has been proposed by researchers in Arizona. This device could be as small as a single benzene molecule, and would produce much less heat than a conventional field effect transistor.

 

Notwithstanding the incredibly shrinking transistor, nanometer-size transistors work on the same principles as much larger ones: current flows into the base (the gate controller) from one electrode (the collector) and out through another (the emitter). The base switches the current on and off by raising and lowering an electrical potential barrier gate that prevents the flow of electrons.

 

Unfortunately, this type of switching requires a lot of power. As more and more transistors are crammed into the same space, the power density, and with it heat dissipation, becomes an overriding issue. At the current rate of miniaturization, by the end of the decade, you might as well be feeling a rocket nozzle than touching a chip; and soon after 2010, computer chips could feel like the bubbly hot surface of the sun itself. " -nanowerk.com Sep 2007