April 21, 2008 In recent decades, manufacturers have crammed more and more components onto integrated circuits, roughly keeping pace with Moore’s Law. But for this to continue the semiconductor industry must overcome the poor stability of materials if shaped in elements smaller than 10 nanometres in size. At this spatial scale, all semiconductors, including silicon, oxidise, decompose and uncontrollably migrate along surfaces like water droplets on a hot plate. Now researchers at the University of Manchester, reporting their peer-reviewed findings in the latest issue of Science, have shown that it is possible to carve out nanometre-scale transistors from a single graphene crystal. Unlike all other known materials, graphene remains highly stable and conductive even when it is cut into devices one nanometre wide.
Graphene is a one-atom-thick gauze of carbon atoms resembling chicken wire discovered in 2004 by Professor Andre Geim and Dr Kostya Novoselov from The School of Physics and Astronomy at The University of Manchester. It is the first known one-atom-thick material which can be viewed as a plane of atoms pulled out from graphite. Graphene has rapidly become a hot topic in physics and materials science with Graphene transistors starting to show advantages and good performance at sizes below 10 nanometres - the miniaturization limit at which the silicon technology is predicted to fail. Their findings show that graphene can be carved into tiny electronic circuits with individual transistors having a size not much larger than that of a molecule and the smaller the size of their transistors the better they perform, say the Manchester researchers.
"Previously, researchers tried to use large molecules as individual transistors to create a new kind of electronic circuits. It is like a bit of chemistry added to computer engineering", says the University’s Dr Kostya Novoselov. "Now one can think of designer molecules acting as transistors connected into designer computer architecture on the basis of the same material (graphene), and use the same fabrication approach that is currently used by semiconductor industry".
"It is too early to promise graphene supercomputers," adds Geim. "In our work, we relied on chance when making such small transistors. Unfortunately, no existing technology allows the cutting materials with true nanometre precision. But this is exactly the same challenge that all post-silicon electronics has to face. At least we now have a material that can meet such a challenge."
Graphene not only promises to extend the life of Moore’s Law, the researchers have also found that the world’s thinnest material absorbs a well-defined fraction of visible light. This promises insights into the "fine structure constant", which defines the interaction between very fast moving electrical charges and light – or electromagnetic waves and like the speed of light, is one of the fundamental constants underlying the very nature of existence.