ION INDUCED SECONDARY ELECTRON EMISSION AS A TOOL FOR NANOSTRUCTURED MATERIAL CHARACTERIZATION

BAJALES, NOELIA; LÖFFLER, DANIEL; BRENNER, PATRICE; BÖTTCHER, ARTUR; KAPPES, MANFRED; FERRÓN, JULIO

La Plata

Congreso; Físico y Química de Superficies; 2009

Universidad Nacional de La Plata

The impact of slow energy ions on metal surfaces is the origin of several physical processes, being the emission of electrons (SEE) one of the most important ones. Several mechanisms, relating the kinetic and potential energy of the incoming ion to the electron generation, have been identified along the last century. In a recent work (PRL 100, 227604 (2008)) we identified one new mechanism operating for ions with large ionization energies on highly oriented pirolitic graphite (HOPG). Namely, the decaying of excitons generated by He+ and Ne+ in HOPG. Being the generation, and surviving, of the exciton related in HOPG with its particular density of states (DOS) and presumably with the asymmetry in the electron conductivity, this mechanism could give us a tool to measure the dimensionality in C based systems, like nanotubes, C60, nano grapheme, etc.. In this work, we present results of SEE induced by the bombardment of 5 keV He+ on nanostructured HOPG. The fabrication of nG were performed by a FIB method recently developed in Karlsruhe. Areas of cm-lateral size of the HOPG surface patterned by arrays of nG stacks were created by combining the Ga+/FIB based writing and application of oxygen-based etching. The geometry of the nG arrays was monitored by means of Atomic Force Microscopy and its DOS by Ultraviolet Photoelectron Spectroscopy.