Water-assisted highly enhanced crystallographic etching of graphene by iron catalysts*
Xue Lei-Jianga), Yu Fangb), Zhou Hai-Qingb)†, Sun Lian-Fengb)‡
       
Typical SEM images showing some irregular channels and the creation of crystallographically oriented nanoribbons after iron etching with water addition. In panel (a), if there are step edges on the surface which hinder the moving of nanoparticles, iron nanoparticles can move straight across these steps without changing direction. Panels (b)—(d) are from the same nanotrenches, from which we can evaluate the relevant channel length up to 10 μm. In these images, no iron catalysts are observed.