14 DAY TRIAL // The ever shrinking transistors in electronic components will soon encounter serious problems with the current silicon materials. Under 20 nm, conventional silicon transistors cannot properly conduct electricity. Predicting the silicon-related problems, scientists started researching other materials for future transistors.
The latest findings present transistors more than four times smaller and more efficiently than the tiniest silicon ones. These improved versions can be made using sheets of carbon just one-tenth of a nanometer thick. The transistors are made of what is called graphene, a sheet of carbon atoms in a flat honeycomb arrangement. Graphene can lead to the creation of graphite when stacked in layers, and carbon nanotubes when rolled into a tube. Graphene is among the best electricity conductors, since electrons can travel through in straight lines between atoms without being scattered. The carbon-derived material will constitute the basis of faster, more efficient electronic components that also require less power. But the most important aspect about graphene is that, unlike other experimental nanoscopic transistors, it requires neither complex manufacturing nor cryogenic cooling.
Thanks to Andre Geim and colleagues at the University of Manchester, UK, the improved graphene transistors are now completely current-leak-free and can efficiently control the flow of just a single electron. The leak-free transistor is made of a "nano-ribbon" of graphene less than 10 nanometers wide and just a single carbon atom thick (0.1 nm). One thin strip of graphene constrains the quantum energy levels available to flowing electrons, preventing them from hopping around and leading to energy leaks. An electric field is used to control this flow, tweaking the energy levels to switch the current on and off.
Edward McCann at Lancaster University, UK, expects to see increasing computer-company investment in research into potential uses of graphene. "This new material has properties that suggest it could have a range of powerful applications," McCann claims.