INVESTIGADORES
ALDAO celso Manuel
artículos
Título:
Temperature Dependent Al/GaAs(110) Interface Formation and Adatom Energy References
Autor/es:
S.G. ANDERSON; C.M. ALDAO; G.D. WADDILL; I.M. VITOMIROV; S.J. SEVERTSON; J.H. WEAVER
Revista:
PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS
Editorial:
APS
Referencias:
Año: 1989 vol. 40 p. 8305 - 8312
ISSN:
0163-1829
Resumen:
Synchrotron-radiation photoemission studies of the formation of Al/GaAs(110) interfaces have
been performed as a function of substrate temperature for 60~ T~ 300 K for n- and p-type doped
samples. The results show temperature-dependent changes in surface Fermi-level position, surface
morphology, and the distribution of released substrate atoms in the overlayer. Detailed examination
shows a separation in energy of ?1.0 eV for the Al 2p binding energy for n- and p-type GaAs
at low coverage. This equals the difFerence in band bending for the two substrates and demonstrates
that the adatom energy reference is an intrinsic level of the semiconductor, not the Fermi level.
Substrate band bending approaches its final value when EF becomes the energy reference for the
overlayer, and this occurs at the onset of metallic overlayer behavior. Temperature-dependent band
bending observed below ?1 monolayer can be understood in terms of the coupling of an adsorbate
energy level to the semiconductor via steady-state tunneling and thermionic emission. The highcoverage
results at all temperatures are consistent with metallicity.