Enhancing gas induced charge doping in graphene field effect transistors by non-covalent functionalization with polyethyleneimine

摘要

We demonstrate that large-area, graphene field effect transistors with a passive parylene substrate and a polyethyleneimine functional layer have enhanced sensitivity to CO_2 gas exposure. The electron doping of graphene, caused by protonated amine groups within the polyethyleneimine, is modulated by the formation of negatively charged species generated by CO_2 adsorption. The charge doping mechanism is general, and quantitative doping density changes can be determined from the graphene field effect transistor characteristics. © 2072 American Institute of Physics.