Trapping effects on charge transport in graphene field-effect transistors with high-K gate dielectrics

Abstract

This paper investigates near-interfacial charge trapping effects in graphene field-effect transistors with high-K gate dielectrics. Experimental and model-based analysis elucidates the impact of trapped charge on the transport properties of graphene. Landauer formalism is applied to correlate trapping-enhanced charged impurity scattering to degradation in conductivity and mobility. The analysis shows a significant reduction in conductivity and mobility with a transition toward the dominance of charge impurity scattering as evidenced by their dependence on the sheet carrier density. Moreover, we quantify the impact of trapped charge buildup on the carrier backscattering mean free path associated with charged impurities. This work provides new insights into the impact of charge trapping toward the development of logic, memory, and neuromorphic devices based on graphene and other low-dimensional materials and ultrascaled high-K dielectrics.