AVS 50th International Symposium
    Surface Science Tuesday Sessions
       Session SS2-TuA

Paper SS2-TuA8
A Self-Assembled Two Dimensional Electron Gas: @sr@7x@sr@3 In on Si(111)

Tuesday, November 4, 2003, 4:20 pm, Room 327

Session: Surfaces and Interfaces of Semiconductors and Compound Materials
Presenter: E. Rotenberg, Lawrence Berkeley National Laboratory
Authors: E. Rotenberg, Lawrence Berkeley National Laboratory
H. Koh, Lawrence Berkeley National Laboratory
H.W. Yeom, Yonsei University, Korea
J. Schaefer, University of Augsberg, Germany
B. Krenzer, University of Oregon
M. Rocha, University of Oregon
S.D. Kevan, University of Oregon
Correspondent: Click to Email
We present low-temperature, high-resolution photoemission measurements of the Fermi surface and bandstructure of single-domain @sr@7x@sr@3 Indium on Si(111). Electrons from both indium valence electrons and the silicon dangling bonds form a nearly free, two-dimensional electron gas (2DEG) on a pseudosquare lattice, which is almost completely decoupled from the underlying hexagonal silicon lattice at the Fermi level. Structural analysis with LEED and photoelectron diffraction is consistent with the pseudo-four-fold structure, and rule out both pseudo-six-fold as well as triple (120°-rotated) domains which were reported in previous studies. About half of the Si dangling bond electrons are donated directly to the 2DEG, while the remainder form three bands -- confined to relatively small regions of k-space -- which we associate with In/Si covalent bond formation. The mean free path of carriers in the 2DEG is found to be at least 500 Å along the interface.