Changing graphene properties
Electrons in graphene behave as massless particles with extremely high mobility. Tailoring graphene’s properties, by opening a band gap, introducing magnetism, or transforming a graphene sheet into a transistor or sensor, offers many promising applications. Hydrogenation is one approach to modify graphene’s properties, potentially allowing in-plane structuring. Nevertheless, several open questions remain for practical applications, particularly regarding the stability of hydrogenation (under temperature variations or in biological environments) and the resulting charge carrier mobility. These last parts are still under work.
Topics
Hydrogenation
Although graphite can be hydrogenated under pressure (ref), its quality remains poor (ref) compared to rGO after annealing at 400°C. With one side of the graphene hydrogenated, the pristine graphene can be recovered after annealing at 300°C (our work). In practice, hydrogenation is removed in air at 150–200 °C (our experience).
With graphite, a limit of 300°C is also reported (ref). Depending on the deposition conditions, etching can compete with hydrogenation (our work).
Devices
Only one study on a transistor using single-side fluorinated graphene has been reported by Moon et al. (ref) but without time response. Our data obtained with less-fluorinated graphene show a reduction in carrier mobility. Since hydrogenation can be partially removed during clean-room processing (e.g., by solvents) and is highly sensitive to temperature, the device should be fabricated first and hydrogenated afterwards. This work on a transistor with hydrogenated graphene layer is still ongoing.
Web sites of interest
Xlynx (first available bulk graphane)
Atomic hydrogen (MBE)
Project funded by French National Research Agency (ANR)
Principal Investigator
Pascal Puech
Website design
Patrice Amoyel, 2022
