Impacts of channel constriction dimensions of graphene single-carrier transistors on the coulomb diamond characteristics

We present a new engineering method to achieve high-performance graphene single-carrier transistors (GSCTs) by suppressing the formation of unwanted carrier (electrons/holes) puddles in GSCTs by comparing the three devices with different constriction dimensions. GSCTs with wider and longer constrictions exhibited the presence of multiple carrier puddles in the channel regions. The GSCTs with narrower constrictions showed the fully-lifted blockade regions in the Coulomb diamond characteristics, which indicate the absence of the multiple quantum dots in the channel. As the channel constrictions size is reduced to the graphene intrinsic carrier puddles dimension, formation of unwanted carrier puddles is avoided.