Long-range migration of H-atoms from electron-induced dissociation of HS on Si(111).
J Phys Condens Matter
; 33(47)2021 Sep 08.
Article
em En
| MEDLINE
| ID: mdl-34407523
ABSTRACT
The electron-induced dissociation of chemisorbed HS to give recoiling H-atoms was investigated on a Si(111)-7 × 7 surface at 270 K by scanning tunnelling microscopy and modelled by density functional theory. Two different H-atom migratory pathways were identified 'short-range' (S-R; 37%) and 'long-range' (L-R; 42%). In S-R reaction the H-atom recoiled by only 4 Å whereas in L-R the average H-recoil distance was 17 Å extending up to 72 Å. Chemisorbed H-atoms were not detected in the remaining 22% of dissociative events. Excitation involved three successive events, e-+ HS. Molecular dynamics calculations of S-R and L-R recoil of H-atoms were performed using a model based on electron-induced H â
S repulsion. In S-R the repulsion gave the H-atom sufficient energy to dissociate HS, but not enough to result in capture of the H-atom by the adjacent rest Si-atom. In L-R a higher translational energy of the recoiling H, above 0.2 eV, caused the H-atom to 'bounce' off surface atoms and migrate L-R. The finding that H-atom L-R migration followed the ballistics and 'bounce' mechanism is indicative of the generality of this mode of L-R recoil.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
J Phys Condens Matter
Assunto da revista:
BIOFISICA
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Canadá