Charge transfer hysteresis in graphene dual-dielectric memory cell structures

We report controlled charge transfer between large-area graphene and a dual-dielectric, silicon nitride/silicon oxide substrate. Graphene was grown on copper by chemical vapour deposition, transferred to the nitride substrates, and patterned into test structures. Hysteresis in conductance with varying gate voltage is easily understood in terms of electron transfer between graphene and nitride traps. Increased hysteresis with temperature suggests thermally activated charge transfer of a Poole-Frenkel or Schottky nature. A 7.3x change in graphene sheet resistance is observed at room temperature with the nitride in a charged and discharged state. (C) 2011 American Institute of Physics. [doi:10.1063/1.3630227]