Room-Temperature High On/Off Ratio in Suspended Graphene Nanoribbon   Field Effect Transistors
  We have fabricated suspended few layer (1-3 layers) graphene nanoribbon field effect transistors from unzipped multiwall carbon nanotubes. Electrical transport measurements show that current-annealing effectively removes the impurities on the suspended graphene nanoribbons, uncovering the intrinsic ambipolar transfer characteristic of graphene. Further increasing the annealing current creates a narrow constriction in the ribbon, leading to the formation of a large band-gap and subsequent high on/off ratio (which can exceed 104). Such fabricated devices are thermally and mechanically stable: repeated thermal cycling has little effect on their electrical properties. This work shows for the first time that ambipolar field effect characteristics and high on/off ratios at room temperature can be achieved in relatively wide graphene nanoribbon (15 nm ~50 nm) by controlled current annealing. 
Ming-Wei Lin, Cheng Ling, Yiyang Zhang, Hyeun Joong Yoon, Mark   Ming-Cheng Cheng, Luis A. Agapito, Nicholas Kioussis, Noppi...
cond-mat.mes-hall cond-mat.mtrl-sci