(706c) Micro-Nanoscale Tuneable Reduction of Graphene/Graphite Oxide Via Focused Ion Beam Irradiation

Graphene has risen to prominence as a versatile and scientifically intriguing material with unparalleled potential for application in electronics. Consequently, control of its properties and its fabrication are key research focuses toward realisation of this potential. An intriguing and innovative route to property-controlled synthesis of graphene is spatially patterned reduction of graphene oxide (GO) which allows fabrication of conductive reduced-graphene oxide (rGO) pathways into an otherwise electrically insulating (GO) material with a focussed ion beam (FIB). Dual FIB-SEM systems are a common feature of all modern microscopy centres therefore the importance and relevance of using FIB irradiation to achieve this goal is rising in prominence. FIB irradiation also has a number of particular advantages including direct imprinting of complex micron-scale shapes and sub-20nm lines of rGO in insulating films/flakes of GO. FIB irradiation can also be controlled such that degrees of reduction can be obtained, including amorphisation of the sample. This tuneable reduction method can be of significance in the quest towards wholly carbon based electronics and allows us to control not only the chemical makeup of the substrate but also its porosity, roughness and most importantly its electrical conductivity.

FIB technology gives us the ability to control each of these parameters across a wide range of length scales and to miniaturise the entire process which is crucial to fabricate nanoscale devices, parameters which are also important in the creation of future all-carbon super-capacitors. Thus, the ability to control patterned features varying in size from ~10’s nm to ~100’s of μm, in a mask-less and efficient manner, can be established as a crucial step towards graphene electronic devices.

We present proof-of-concept experimental results of the controlled reduction¹and amorphisation process including a detailed study of the regimes of reduction and amorphisation of GO flakes with respect to the incident ion dosage.

1              Lobo, D. E., Fu, J., Gengenbach, T. & Majumder, M. Localized Deoxygenation and Direct Patterning of Graphene Oxide Films by Focused Ion Beams. Langmuir 28, 14815-14821, doi:10.1021/la303369m (2012).