BALLISTIC ELECTRONS

摘要

In general, the thinner a solid material is, the lower its conductivity becomes: there is less space for electrons to manoeuvre without colliding with rough surfaces, being captured by atoms of other elements present as impurities within the crystal, or being pushed off course by atomic vibrations. In an ultra-high vacuum and at ultra-low temperatures, vibrations and the effects of impurities are suppressed, which does help a little. Yet graphene's one-atom-thick film has better electronic qualities than any three-dimensional material, whether a metal like gold or a semiconductor like silicon - and not just at low temperatures.