Programmable graphene doping via electron beam irradiation
  Graphene is a promising candidate to succeed silicon based devices and doping holds the key to graphene electronics. Conventional doping methods through surface functionalization or lattice modification are effective in tuning carrier densities. These processes, however, lead to degradation of device performance because of structural defect creation. A challenge remains to controllably dope graphene while preserving its superlative properties. Here we show a novel method for tunable and erasable doping of on-chip graphene, realized by using a focused electron beam. Our results demonstrate site-specific control of carrier type and concentration achievable by modulating the charge distribution in the dielectric substrate. Thereby, the structural integrity and electrical performance of graphene are preserved, and the doping states are rewritable. Different logic operations were thus implemented in a single graphene sheet. By extending this method to other two-dimensional materials, this work lays out a blueprint for powerful yet simple means of incorporating two-dimensional materials into prospective electronic technologies. 
Yangbo Zhou, Jakub Jadwiszczak, Darragh Keane, Ying Chen, Dapeng Yu,   Hongzhou Zhang
cond-mat.mes-hall