A road to hydrogenating graphene by a reactive ion etching plasma

TL;DR

This paper demonstrates a controlled method for hydrogenating graphene using an argon-hydrogen plasma in a reactive ion etching system, linking defect levels to electronic properties without significant damage.

Contribution

It introduces a plasma-based hydrogenation technique for graphene that allows precise control and minimal damage, adaptable to standard RIE systems.

Findings

Hydrogenation level correlates with defect concentration.

Self-bias suppresses graphene erosion during plasma treatment.

Hydrogenation occurs mainly from plasma hydrogen ions, not water fragmentation.

Abstract

We report the hydrogenation of single and bilayer graphene by an argon-hydrogen plasma produced in a reactive ion etching (RIE) system. Electronic transport measurements in combination with Raman spectroscopy are used to link the electric mean free path to the optically extracted defect concentration. We emphasize the role of the self-bias of the graphene in suppressing the erosion of the akes during plasma processing. We show that under the chosen plasma conditions the process does not introduce considerable damage to the graphene sheet and that hydrogenation occurs primarily due to the hydrogen ions from the plasma and not due to fragmentation of water adsorbates on the graphene surface by highly accelerated plasma electrons. For this reason the hydrogenation level can be precisely controlled. The hydrogenation process presented here can be easily implemented in any RIE plasma system.