Defect formation by single ion impacts on highly oriented pyrolytic graphite observed by scanning tunneling microscopy
- Univ. Goettingen (Germany). Physikalisches Inst.
(0001) surfaces of highly oriented pyrolytic graphite (HOPG) were irradiated at 77K with {sup 132}Xe{sup +} ions at energies between 50 keV and 900 keV. The ion fluences ranged between 10{sup 11} ions/cm{sup 2} and 10{sup 15} ions/cm{sup 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 {angstrom}. 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{degree} 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.
- OSTI ID:
- 375953
- Report Number(s):
- CONF-941144-; ISBN 1-55899-255-3; TRN: IM9642%%41
- Resource Relation:
- Conference: Fall meeting of the Materials Research Society (MRS), Boston, MA (United States), 28 Nov - 9 Dec 1994; Other Information: PBD: 1995; Related Information: Is Part Of Beam-solid interactions for materials synthesis and characterization; Jacobson, D.C. [ed.] [AT and T Bell Labs., Murray Hill, NJ (United States)]; Luzzi, D.E. [ed.] [Univ. of Pennsylvania, Philadelphia, PA (United States)]; Heinz, T.F. [ed.] [Columbia Univ., New York, NY (United States)]; Iwaki, Masaya [ed.] [Inst. of Physical and Chemical Research, Wako, Saitama (Japan)]; PB: 763 p.; Materials Research Society symposium proceedings, Volume 354
- Country of Publication:
- United States
- Language:
- English
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