INVESTIGADORES
ALDAO celso Manuel
artículos
Título:
Disruption, Atom Distributions, and Energy Levels for Ge/GaAs(110), Ge/InP(110), and Ge/InSb(110) Heterojunctions
Autor/es:
C.M. ALDAO; I.M. VITOMIROV; F. XU; J.H. WEAVER
Revista:
PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS
Editorial:
APS
Referencias:
Año: 1989 vol. 40 p. 3711 - 3719
ISSN:
0163-1829
Resumen:
We report a detailed room-temperature synchrotron-radiation photoemission study of Ge overlayer
growth on n-type GaAs(110), InP(110), and InSb(110) in order to correlate changes in bonding
configurations and atom distribution with the movement of the Fermi level in the substrate band
gap and the evolution of the electronic properties of the Ge overlayer. For Ge/GaAs(110), the interface
is abrupt, but substrate core-level line-shape analysis indicates changes in the boundary layer
and unique interface bonding configurations. Ge adatoms induce substrate disruption for InP(110)
and InSb(110), and there are coverage-dependent morphology changes as atoms dissociated from
the substrate redistribute themselves in the thickening Ge overlayer. In atoms segregate to the Ge
surface but exhibit no tendency to form clusters; P atoms remain near the buried Ge/InP interface;
and Sb atoms are expelled to the overlayer surface. The deposition of Ge on GaAs and InP causes
the Fermi level to move toward midgap at low coverage, but then move back toward the conduction
band. The reversal in direction correlates well with changes in substrate core-level line shapes.
Low-temperature studies of Ge/n-type GaAs did not show this reversal, but the final position of EF
in the gap was the same. The fully developed valence-band discontinuities were 0.73, 1.03, and 0.12
eV for amorphous Ge/GaAs(110), Ge/InP(110), and Ge/InSb(110) heterojunctions, respectively.