Buffer Layer Engineering on Graphene via Various Oxidation Methods for   Atomic Layer Deposition
  The integration of high-k oxide on graphene using atomic layer deposition requires an electrically reliable buffer layer. In this study, Y was selected as the buffer layer due to the highest oxidation ability in rare earth elements and various oxidation methods (atmospheric, high-pressure O2 and ozone) were applied to the Y metal buffer layer. By optimizing oxidation conditions of the top gate insulator, we successfully improve the capacitance of top gate Y2O3 insulator and demonstrate a large Ion/Ioff ratio for bilayer graphene under an external electric field. 
Nobuaki Takahashi, and Kosuke Nagashio
cond-mat.mtrl-sci