Impact of contact resistance on the transconductance and linearity of graphene transistors

Interest in graphene device physics and technology has been growing rapidly, especially for very high frequency transistor applications. However, the predicted intrinsic performance has not been fully realized due to impurity and parasitic issues introduced in device fabrication. Through a self-consistent model, we show that the normalized contact resistance has an exponentially detrimental impact on the peak transconductance, which is a defining transistor parameter. In addition, we reveal that very high current-gate voltage linearity or input invariant transconductance can be achieved in the limit of negligible contact resistances, a desirable feature for linear electronic systems.