Internal and External Atomic Steps in Graphite Exhibit Dramatically Different Physical and Chemical Properties - ACS Nano (ACS Publications)
Hyunsoo Lee †‡, Han-Bo-Ram Lee §, Sangku Kwon †‡, Miquel Salmeron *∥, and Jeong Young Park *†‡
DOI: 10.1021/nn506755pPublication
Date (Web): March 27, 2015
Abstract
We report on the physical and chemical properties of atomic steps on the surface of highly oriented pyrolytic graphite (HOPG) investigated using atomic force microscopy. Two types of step edges are identified: internal (formed during crystal growth) and external (formed by mechanical cleavage of bulk HOPG). The external steps exhibit higher friction than the internal steps due to the broken bonds of the exposed edge C atoms, while carbon atoms in the internal steps are not exposed. The reactivity of the atomic steps is manifested in a variety of ways, including the preferential attachment of Pt nanoparticles deposited on HOPG when using atomic layer deposition and KOH clusters formed during drop casting from aqueous solutions. These phenomena imply that only external atomic steps can be used for selective electrodeposition for nanoscale electronic devices
