In:
MRS Proceedings, Springer Science and Business Media LLC, Vol. 354 ( 1994)
Abstract:
(0001) surfaces of highly oriented pyrolytic graphite (HOPG) were irradiated at 77K with 132 Xe + ions at energies between 50 keV and 900 keV. The ion fluences ranged between 10 11 ions/cm 2 and 10 15 ions/cm 2 . Scanning tunneling microscopy (STM) was applied to image the irradiation induced defects at the surfaces. In case of orthogonal incidence and small ion fluence each incident ion induces one single hillock at the surface. These hillocks have typical lateral diameters of 2 nm and heights of several à. In many cases measurements of the hillocks with atomic resolution show disordered atomic arrangements. The hillocks are interpreted as the local volume expansion due to surface-near self-interstitials generated in the collision cascades of the ions. The high mobility of these interstitials parallel to the (0001) planes leads to a formation of interstitial clusters which cause the larger hillocks. Irradiation at an angle of incidence of 75° with respect to the surface normal effects a higher density of hillocks due to the higher number of recoils stopped in the uppermost lattice planes. The hillocks are arranged in chains which are aligned in the direction of the incident beam. Each of these chains marks a single collision cascade.
Type of Medium:
Online Resource
ISSN:
0272-9172
,
1946-4274
DOI:
10.1557/PROC-354-301
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
1994
