Two-dimensional atomic sheets of graphene represent a new class of nanoscale materials with potential applications in electronics. However, exploiting the intrinsic characteristics of graphene devices has been problematic due to impurities and disorder in the surrounding dielectric and graphene/dielectric interfaces. Recent advancements in fabricating graphene heterostructures by alternately layering graphene with crystalline hexagonal boron nitride (hBN), its insulating isomorph, have led to an order of magnitude improvement in graphene device quality. Here, recent developments in graphene devices utilizing boron-nitride dielectrics are reviewed. Field-effect transistor (FET) characteristics of these systems at high bias are examined. Additionally, existing challenges in material synthesis and fabrication and the potential of graphene/BN heterostructures for novel electronic applications are discussed.

The novel electronic properties of graphene, including a linear energy dispersion relation and purely two-dimensional structure, have led to intense research into possible applications of this material in nanoscale devices. In this paper, we review the unique electronic properties of graphene that give it the potential for high frequency electronic applications. We then present the latest results on the current-voltage characteristics of top-gated graphene FETs. These devices show unique characteristics related to the ambipolar nature of the graphene channel. In addition, the devices show very high saturation velocities, suggesting the possibility for superior high frequency performance. Our initial devices have transconductances as high as 150 muS/mum despite low on-off current ratios, making the devices very suitable for analog/RF applications.