Angular distribution of Ga sup + ions desorbed by 3-keV-ion bombardment of GaAs l brace 001 r brace -(2 times 4)

Journal Article · Sun Dec 15 04:00:00 EST 1991 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.44.12830· OSTI ID:5589706

Blumenthal, R; Caffey, K P; Furman, E; Garrison, B J; Winograd, N ^[1]

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1. Department of Chemistry, The Pennsylvania State University, 152 Davey Laboratory, University Park, Pennsylvania 16802 (United States)

The angular distribution of Ga{sup +} ions desorbed from the molecular-beam-epitaxy-grown GaAs{l brace}001{r brace}-(2{times}4) surface by ion bombardment is presented. This distribution displays the highest degree of anisotropy, relative to the crystal direction of desorbed ions, which has been reported to date. The interpretation of the data is possible using physical arguments based on a simple geometric model of the desorption of ions from the surface. Further insight is provided by comparison to molecular-dynamics simulations of the keV-ion bombardment of metal and semiconductor surfaces. The experimental and calculated distributions of Ga{sup +} ions desorbed from the (2{times}4) surface are in reasonable qualitative agreement. The results indicate that the extreme anisotropy in the angular distribution results from a direct mechanism wherein a third-layer As atom collides with a second-layer Ga atom and thereby causes the Ga atom to eject along their mutual bond axis. This mechanism has been observed previously on Si and GaAs surfaces but is not commonly observed on metal surfaces, and can be ascribed to the directional bonding and open structure of covalent crystals. Other features of the angular distribution are related to blocking and channeling of the desorbed Ga{sup +} ions. These features indicate that there is one, and only one, missing row of As{sub 2} dimers for every 16 A unit-cell length along the 4{times} crystal direction. These results provide complementary information which is in excellent agreement with other studies of the GaAs{l brace}001{r brace}-(2{times}4) surface.

• OSTI ID: 5589706
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 44:23; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

665300* -- Interactions Between Beams & Condensed Matter-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANGULAR DISTRIBUTION
ARGON IONS
ARSENIC COMPOUNDS
ARSENIDES
BEAMS
CHARGED PARTICLES
COLLISIONS
DESORPTION
DIMERS
DISTRIBUTION
ENERGY RANGE
EPITAXY
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
GALLIUM IONS
ION BEAMS
ION COLLISIONS
IONS
KEV RANGE
KEV RANGE 01-10
PNICTIDES