By Lishan Weng – Before 2004, when Geim and Novoselov demonstrated the existence of graphene, a single-atomic-layer-thick crystal of carbon, physicists didn’t believe such a substance could exist. Since then, graphene has attracted tremendous research interest because of its exceptional physical and electrical properties, including remarkably high electron mobility at room temperature, high transparency, very high thermal conductivity and superior mechanical strength.
Graphene is highly conductive, so measured voltages are low. The results (Figure) show the longitudinal resistance of the graphene layer as a function of the silicon substrate. They demonstrate graphene’s ambipolar nature; that is, that it conducts when either electrons or holes are induced into the material. The large slope on each side of the peak indicates a rapid decrease in resistance as the magnitude of the gate voltage increases, which offers evidence of graphene’s high carrier mobility. more> http://tinyurl.com/pvkbmm7