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OO6.04 - Towards Lithography-Free Fabrication of Graphene Devices 
April 22, 2014   2:45pm - 3:00pm

Graphene device fabrication on large-area graphene typically involves electron-beam or optical lithography, followed by graphene etching and metallization of contacts. However, this method introduces compatibility issues, such as the difficulty of removing resist material from the graphene. The resulting resist contamination causes undesired doping, leading to a reduction in the charge carrier mobility in the graphene. In this work we therefore developed a direct-write, lithography-free method for the fabrication of graphene devices.In the first step large-area graphene is patterned with a focused ion beam. An in situ Raman microscope allowed for direct observation of the graphene before and after the ion beam processing. Our results show that a Ga-ion dose of 10 C/m2 is sufficient for complete graphene removal. Defects formed by re-deposition or secondary electrons in the graphene away from the ion-milled area were successfully repaired by annealing in an inert atmosphere. In the second step Pt contacts are formed by using our novel resist-free direct-write technique [1, 2]. This approach consists of the patterning of a thin seed layer of less than 0.5 nm Pt-containing material by electron beam induced deposition (EBID), followed by selective thickening of the seed layer by area-selective atomic layer deposition (ALD). This combined approach gives high-quality material (virtually 100% pure Pt, resistivity of 12 μΩcm), while it allows for patterning of Pt line deposits of only 10 nm in width. The electrical transport characteristics of graphene field-effect transistors fabricated using our lithography-free approach will be demonstrated.[1] A.J.M. Mackus, S.A.F. Dielissen, J.J.L. Mulders, W.M.M. Kessels, Nanoscale 4 (2012) 4477[2] A.J.M. Mackus, N.F.W. Thissen, J.J.L. Mulders, P.H.F. Trompenaars, M.A. Verheijen, A.A. Bol, W.M.M. Kessels, J. Phys. Chem. C 117 (2013), 10788

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Keynote Address
Panel Discussion - Different Approaches to Commercializing Materials Research
Business Challenges to Starting a Materials-Based Company
Fred Kavli Distinguished Lectureship in Nanoscience
Application of In-situ X-ray Absorption, Emission and Powder Diffraction Studies in Nanomaterials Research - From the Design of an In-situ Experiment to Data Analysis