Lateral damage in graphene carved by high energy focused gallium ion beams.

Authors :: Zhongquan Liao
Tao Zhang
Gall, Martin
Dianat, Arezoo
Rosenkranz, Rüdiger
Jordan, Rainer
Cuniberti, Gianaurelio
Zschech, Ehrenfried
Source :: Applied Physics Letters; 7/6/2015, Vol. 107 Issue 1, p1-5, 5p, 1 Color Photograph, 2 Charts, 2 Graphs
Publication Year :: 2015
Abstract: Raman mapping is performed to study the lateral damage in supported monolayer graphene carved by 30keV focused Ga<superscript>+</superscript> beams. The evolution of the lateral damage is tracked based on the profiles of the intensity ratio between the D (1341cm<superscript>-1</superscript>) and G (1582cm<superscript>-1</superscript>) peaks (I<subscript>D</subscript>/I<subscript>G</subscript>) of the Raman spectra. The I<subscript>D</subscript>/I<subscript>G</subscript> profile clearly reveals the transition from stage 2 disorder into stage 1 disorder in graphene along the direction away from the carved area. The critical lateral damage distance spans from <1μm up to more than 30μm in the experiment, depending on the parameters used for carving the graphene. The wide damage in the lateral direction is attributed to the deleterious tail of unfocused ions in the ion beam probe. The study raises the attention on potential sample damage during direct patterning of graphene nanostructures using the focused ion beam technique. Minimizing the total carving time is recommended to mitigate the lateral damage. [ABSTRACT FROM AUTHOR]