Regensburg 2004 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
HL: Halbleiterphysik
HL 44: Poster II
HL 44.80: Poster
Donnerstag, 11. März 2004, 16:30–19:00, Poster A
Infrared and VIS/UV optical properties of GaN/AlN superlattices grown on Si substrate — •A. Kasic1, B. Monemar1, M. Schubert2, A. Dadgar3, F. Schulze3, and A. Krost3 — 1Linköping University, Department of Physics and Measurement Technology, S-581 83 Linköping, Sweden — 2Universität Leipzig, Institut für Experimentelle Physik II, Linnéstr. 5, 04103 Leipzig — 3Otto-von-Guericke-Universität Magdeburg, Institut für Experimentelle Physik, Universitätsplatz 2, 39016 Magdeburg
We report optical properties of 20-period GaN/AlN superlattice (SL) structures from the mid-infrared to the ultraviolet spectral range. The MOCVD-grown hexagonal SL structures with effective Al-content of 24% were either intentionally undoped, Si- or Mg-doped, and deposited on Si substrate using SiN in-situ masks and AlN interlayers.
Infrared ellipsometry spectra reveal a superlattice-related LO phonon mode of A1 symmetry, which is subject to a distinct blue shift towards the respective value for AlN with increasing SL sublayer dimensions. Information on the SL strain is extracted from the phonon modes of the GaN- and AlN-SL sublayers.
Regarding the SL’s as effective homogeneous mediums, their UV dielectric function properties are examined by spectroscopic ellipsometry. Quantum-size affected electronic band-to-band-transitions of the superlattice structures are observed and compared to photoluminescence measurements.