INVESTIGADORES
ALDAO celso Manuel
artículos
Título:
Metal-InP(110) Schottky Barriers: Temperature-, Dopant Concentration-, and Cluster-Deposition Dependencies
Autor/es:
I.M. VITOMIROV; C.M. ALDAO; G.D. WADDILL; C. CAPASSO; J.H. WEAVER
Revista:
PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS
Editorial:
APS
Referencias:
Año: 1990 vol. 41 p. 8465 - 8476
ISSN:
0163-1829
Resumen:
Synchrotron-radiation photoemission has been used to investigate the movement of the surface
Fermi level, EF, in the gap as a function of temperature, bulk dopant concentration, and the technique
of interface formation for Ag/InP(110) and Ti/InP(110). Studies involving atom deposition at
300 and 60 K reveal temperature-independent substrate disruption with substrate retreat that is estimated
to be -4.4 monolayers (ML) for Ti and -1 ML for Ag deposition. Atom distributions
differ, however, because In atoms released by substrate disruption are kinetically trapped near the
interface at 60 K but they are distributed in and atop the metal overlayer at 300 K. Moreover, Ag
deposition at 60 K produces uniform overlayers because of restricted surface mobility whereas Ag
clustering occurs for atom deposition at 300 K. Despite these significant differences in interface
chemistry and morphology, both overlayers induce very different amounts of band bending at 60 K
than at 300 K for n-type InP(110) doped at 4X 10"cm '. This temperature-dependent difference in
band bending is significantly smaller for n- and p-type InP(110) doped at 2.5 X 10"crn '. At higher
coverage above the metallization threshold, the Schottky-barrier height is largely independent of
substrate dopant concentration or measurement temperature but exhibits metal-specific values for
Ag and Ti overlayers. The relationship between EF movement and the details of interfacial bonding
and morphology has been further examined by depositing preformed Ag clusters (rather than
atoms) on pristine InP(110) surfaces. For cluster deposition, there was no noticeable substrate disruption
and the Fermi-level position was not dependent on the size or number of clusters. This indicates
that changes in surface relaxation under and around the clusters introduce states that determine
band bending.