I supported the work of my colleague Ulrich Stuetzel for a while now and a nice paper came out of his thesis. He really prepared very good graphene nanoribbons. Even after ambient processing in acid (and what not) we were able to image the graphite ridges with atomic resolution on top. Never published that, but below is how the photocurrent images look like in the paper. Nice work of Ulrich.
Spatially resolved photocurrents in graphene nanoribbon devices
Eberhard Ulrich Stützel, Thomas Dufaux, Adarsh Sagar, Stephan Rauschenbach, Kannan Balasubramanian, Marko Burghard and Klaus Kern
Applied Physics Letters 102 (2013) 043106