Graphene Electrodes as Barrier-Free Contacts for Carbon Nanotube Field-Effect Transistors

This work evaluates the performance of carbon nanotube field-effect transistors (CNTFETs) using few layer graphene as the contact electrode material. We present the experimental results of the barrier height at carbon nanotube-graphene junction using temperature dependent I-V measurements. The estimated barrier height in our devices for both holes and electrons is close to zero indicating the ohmic contact of graphene for both p-type and n-type CNTFETs thus demonstrating the suitability of graphene as electrode material for CMOS-type circuits based on CNTFETs. Furthermore, we observe that there is no correlation between the barrier height and thickness of graphene.