IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Semiconductors Friday Sessions
       Session SC+SS-FrM

Paper SC+SS-FrM10
Electronic Structure of a Heteroepitaxially-Passivated Si(111) Surface: GaSe-terminated Si(111)

Friday, November 2, 2001, 11:20 am, Room 111

Session: Growth and Epitaxy of Semiconductors
Presenter: M.A. Olmstead, University of Washington
Authors: M.A. Olmstead, University of Washington
R. Rudolf, Hahn-Meitner Inst., Germany
C. Pettenkofer, Hahn-Meitner Inst., Germany
A.A. Bostwick, University of Washington
J.A. Adams, University of Washington
E. Rotenberg, Advanced Light Source, Berkeley
F.S. Ohuchi, University of Washington
R. Fritsche, Tech. Univ. Darmstadt, Germany
A. Klein, Tech. Univ. Darmstadt, Germany
W. Jaegermann, Tech. Univ. Darmstadt, Germany
Correspondent: Click to Email
Dissimilar materials heteroepitaxy often results in an interface reaction that passivates substrate dangling bonds. This forms a low energy surface that promotes islanded, rather than laminar, growth of the subsequent overlayer. GaSe-terminated Si(111) is an example of such a stable, low-diffusion barrier surface with no states in the Si band gap; it may serve as an ideal substrate for quantum dot growth on Si(111). We have performed detailed studies of the electronic and atomic structure of GaSe-terminated S i(111) using energy-dependent and angle-resolved valence band and core-level photoemission spectroscopy. The surface termination consists of a Ga layer bonded to the top-most Si atoms and a Se layer on top with each Se atom bonded to three Ga. Our photoelectron diffraction results show the Ga and Se atomic arrangement is identical to that of a half-sheet of the layered semiconductor GaSe. The surface thus contains no dangling bonds, but has fully-occupied lone-pair states similar to As-terminated Si(111). The observed dispersion of the energy bands is very close to those of a GaSe single crystal and is interpreted in terms of tight binding energy states. The dominance of the GaSe-derived states over those of Si-derived states is obvious and is different from As-terminated Si.