Graphene Thickness-Graded Transistors with Reduced Low-Frequency 1/f   Noise
  We demonstrate graphene thickness-graded transistors with high electron mobility and low 1/f noise (f is a frequency). The device channel is implemented with few-layer graphene with the thickness varied from a single layer in the middle to few-layers at the source and drain contacts. It was found that such devices have electron mobility comparable to the reference single-layer graphene devices while producing lower noise levels. The metal doping of graphene and difference in the electron density of states between the single-layer and few-layer graphene cause the observed noise reduction. The results shed light on the noise origin in graphene. 
Guanxiong Liu, Sergey Rumyantsev, Michael Shur and Alexander A.   Balandin
cond-mat.mes-hall cond-mat.mtrl-sci