Münster 1999 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 23: Poster II
HL 23.72: Poster
Mittwoch, 24. März 1999, 14:00–18:00, Z
Angle Resolved Photoemission Spectroscopy of GaN(1010): Experiment and Theory — •L. Tarcak1, J. Wichert1, R. Weber1, L. Kipp1, M. Skibowski1, T. Strasser2, F. Starrost2, C. Solterbeck2, W. Schattke2, T. Suski3, I. Grzegory3, and S. Porowski3 — 1Institut für Experimentelle und Angewandte Physik, Universität Kiel — 2Institut für Theoretische Physik und Astrophysik, Universität Kiel — 3UNIPRESS, Polish Academy of Science, 01-142 Warszawa, Poland
In recent years photoemission studies of GaN
concentrated on epitaxially grown samples. The aim
of this work was the determination of the electronic
structure of the non-polar wurtzite
GaN(1010)-surface.
The samples of GaN single crystals grown by high pressure,
high temperature synthesis were
cleaved under ultra high vacuum conditions. For
the measurements we used synchrotron radiation of
a SX 700-monochromator and a 3m-normal
incidence monochromator in the energy range from
10eV-150eV at HASYLAB. The surface and bulk
valence band structure was examined in normal
emission along Γ M and in off-normal emission
along Γ X and
Γ X′.
Theoretical photocurrent calculations
within the highly accurate one-step model were performed.
For the calculations the surface model by Neugebauer
et al. [1] was used. The results were
analysed with respect to matrix elements, density
of states and direct transitions. Comparing
theoretical and experimental photocurrents we could
identify the valence band maximum as well as
emissions from surface states and resonances near
the upper and lower valence band edge.
This work was supported by BMBF project no.
05 SE8 FKA and 05 SB8 FKB.
[1] J. E. Northrup, J. Neugebauer, Phys. Rev. B 53(16), R10477 (1996)