Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 4: GaN: Preparation and Characterization I (mainly Optics)
HL 4.6: Vortrag
Montag, 26. März 2012, 10:45–11:00, EW 201
Optical studies on doped and nominally undoped AlN layers — •Benjamin Neuschl1, Martin Feneberg2, María Fátima Romero2, Rüdiger Goldhahn2, Zhihong Yang3, Thomas Wunderer3, Jinquiao Xie4, Seiji Mita4, Anthony Rice5, Ramón Collazo5, Zlatko Sitar5, and Klaus Thonke1 — 1Institute of Quantum Matter / Group Semiconductor Physics, University of Ulm, Ulm — 2Institut für Experimentelle Physik, Abteilung Materialphysik, Otto-von-Guericke-Universität Magdeburg, Magdeburg — 3Palo Alto Research Center Inc., Palo Alto, California, USA — 4HexaTech Inc., Morrisville, North Carolina, USA — 5Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina, USA
We present optical spectroscopy studies in the near band edge region on high quality c-plane aluminum nitride (AlN) samples grown homoepitaxially by MOCVD on bulk AlN substrates. We analyze the near band edge region in detail by highly energy resolved photoluminescence, reflectivity and photoluminescence excitation spectroscopy. The linewidth of the bound exciton emission peak is as low as 500 µeV and demonstrates thus the excellent crystalline quality of the samples. Multiple sharp emission bands were found in the range from the free exciton to the bound excitons and their replicas. Correlations allow for a direct calculation of defect binding energies. Beyond, spectral contributions from excited exciton states and excitons with holes from the deeper valence band are analyzed.