Columbia Engineering researchers have experimentally demonstrated for the first time that it is possible to electrically contact an atomically thin two-dimensional (2D) material only along its one-dimensional (1D) edge, rather than contacting it from the top, which has been the conventional approach. With this new contact architecture, they have developed a new assembly technique for layered materials that prevents contamination at the interfaces, and, using graphene as the model 2D material, show that these two methods in combination result in the cleanest graphene yet realized. The study is published in Science on November 1, 2013.
Close-up of pure-edge contact in graphene
“This is an exciting new paradigm in materials engineering where instead of the conventional approach of layer by layer growth, hybrid materials can now be fabricated by mechanical assembly of constituent 2D crystals,” says Electrical Engineering Professor Ken Shepard, co-author of the paper. “No other group has been able to successfully achieve a pure edge-contact geometry to 2D materials such as graphene.”
He adds that earlier efforts have looked at how to improve ‘top contacts’ by additional engineering such as adding dopants: “Our novel edge-contact geometry provides more efficient contact than the conventional geometry without the need for further complex processing. There are now many more possibilities in the pursuit of both device applications and fundamental physics explorations.”.......................