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HL: Fachverband Halbleiterphysik

HL 45: Group-III-Nitrides: Optical Properties II

HL 45.10: Vortrag

Mittwoch, 24. März 2010, 17:00–17:15, H15

Optical properties of homoepitaxial AlN — •Martin Feneberg¹, Benjamin Neuschl¹, Ramon Collazo², Anthony Rice², Zlatko Sitar², Jinqiao Xie³, Seiji Mita³, Georg Rossbach⁴, Rüdiger Goldhahn⁴, Marcus Roeppischer⁵, Christoph Cobet⁵, Norbert Esser⁵, and Klaus Thonke¹ — ¹Institut für Halbleiterphysik, Universität Ulm — ²Dept. of Mat. Sci. Engr., North Carolina State University, USA — ³HexaTech, Inc., Morrisville, NC, USA — ⁴Institut für Physik, TU Ilmenau — ⁵ISAS, Berlin

Homoepitaxial c- and m-plane AlN layers, deposited by MOCVD on bulk PVT AlN are investigated by means of high resolution photoluminescence and spetroscopic ellipsometry. We find donor bound exciton lines with a full width at half maximum below 500 µeV at T = 10 K. The exciton binding energy amounts to 52 meV in the c-plane sample leading to a bandgap energy of 6.092 eV (at 10 K). By spectroscopic ellipsometry we access both the ordinary and the extraordinary dielectric functions. The analysis of the sharp free exciton resonance found in the extraordinary tensor components yields a transition energy being in excellent agreement with the emission studies. The ordinary component exhibits a feature which indicates a strong contribution of exciton-phonon interaction to the absorption process.