Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 31: III-V-Compounds: Nitrides
HL 31.11: Vortrag
Dienstag, 15. März 2011, 13:00–13:15, POT 51
Point defects in AlN — •Jan E. Stehr1, Detlev M. Hofmann1, Bruno K. Meyer1, and Matthias Bickermann2 — 11st Physics Institute, Justus-Liebig-University Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany — 2Department of Materials Science 6, University of Erlangen, Martensstraße 7, 91058 Erlangen, Germany
Aluminum nitride (AlN) bulk crystals are due to their high thermal conductivity and the low lattice mismatch a promising substrate material for group III-element-nitrides, e.g. AlGaN. AlN has a band gap of 6.2 eV, but shows a sub-band-absorption, which is a problem for many applications. Therefore it is necessary to understand which defects are responsible for the absorption bands in the crystals. We investigated AlN bulk crystals with UV-VIS spectroscopy and Electron Paramagnetic Resonance spectroscopy (EPR). In the EPR measurements we observe a donor signal with g=1.994 and an acceptor signal with g=2.006. UV-VIS measurements show an optical absorption band at 580 nm. By Photo-EPR we can correlate the absorption band with the EPR signals, which show up after illumination of the sample with light wavelengths shorter than 580 nm. Defect models will be discussed at the conference.