In the previous articles we have talked about memories, whose potentiality and functionality are rapidly increasing due to the advancement in nano technology. I this article we move forward to one upper level by introducing the duality of random access memory and flash memory.
We all know random access memories require constant power to offer their fast access speeds, but can't be scaled to as small a size as slower nonvolatile flash memories. Now researchers believe they can combine the high-speed of RAM with the nonvolatility of flash by using telescopic nanotubes.
Ultra-dense nano-electro-mechanical system (NEMS) arrays could offer molecular sized memory cells that are as fast as RAM but nonvolatile like flash by harnessing concentric nanotubes that turn bits on(1) and off(0) by running current through the tubes to make the inner one stick out or stay inside the outer nanotube.
A study has been going on aimed at replacing silicon-based memory technologies with carbon-based concentric telescopic nanotubes that measure only a few nanometers in diameter. This NEMS approach uses the mechanical movement of nanotube telescoping in and out of concentric tubes to either contact or break contact with a molecular-sized electrode, thus combining the speed of RAM with the non-volatility of flash memory.
To change a bit's state, current would be run through the nanotube, causing electrostatic forces to move the inner nanotube either into or out of the outer nanotube—depending on the direction of current flow. Once a bit has been flipped, power could be removed while the bit stays locked to retain its state indefinitely since van der Waals forces would attract the concentric tubes to each other.
Other potential applications of the telescopic nanotubes include drug delivery to individual cells and nano-sized thermometers which can differentiate between healthy and cancerous cells.
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