Computers are getting smaller and smaller. And as hand-held devices from mobile phones and cameras to music players and laptops get more powerful, the race is on to develop memory formats that can satisfy the ever-growing demand for information storage on tiny formats.
Researchers at The University of Nottingham are now exploring ways of exploiting the unique properties of carbon nanotubes to create a cheap and compact memory cell that uses little power and writes information at high speeds.
Miniaturisation of computer devices involves continual improvement and shrinking of their basic element, the transistor. This process could soon reach its fundamental limit. As transistors approach nanoscales their operation is disrupted by quantum phenomena, such as electrons tunnelling through the barriers between wires.
Current memory technologies fall into three separate groups: dynamic random access memory (DRAM), which is the cheapest method; static random access memory (SRAM), which is the fastest memory but both DRAM and SRAM require an external power supply to retain data; and flash memory, which is non-volatile it does not need a power supply to retain data, but has slower read-write cycles than DRAM.
Carbon nanotubes tubes made from rolled graphite sheets just one carbon atom thick could provide the answer. If one nanotube sits inside another slightly larger one, the inner tube will 'float' within the outer, responding to electrostatic, van der Waals and capillary forces. Passing power through the nanotubes allows the inner tube to be pushed in and out of the outer tube. This telescoping action can either connect or disconnect the inner tube to an electrode, creating the 'zero' or 'one' states required to store information using binary code. When the power source is switched off, van der Waals force which governs attraction between molecules keeps the Inner tube in contact with the electrode. This makes the memory st
|Contact: Tara de Cozar|
University of Nottingham