Electron beam induced etching of carbon

Nanopatterning of graphene and diamond by low energy (<= 30 keV) electrons has previously been attributed to mechanisms that include atomic displacements caused by knock-on, electron beam heating, sputtering by ionized gas molecules, and chemical etching driven by a number of gases that include N-2. Here, we show that a number of these mechanisms are insignificant, and the nanopatterning process can instead be explained by etching caused by electron induced dissociation of residual H2O molecules. Our results have significant practical implications for gas-mediated electron beam nanopatterning techniques and help elucidate the underlying mechanisms. (C) 2015 AIP Publishing LLC.