Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 62: Gallium Nitride: Optical and Electronic Properties
HL 62.8: Vortrag
Mittwoch, 9. März 2016, 17:00–17:15, H17
Defect analysis of (1122) semipolar GaN materials and devices — •Matthias Hocker1, Ingo Tischer1, Marian Caliebe2, Ferdinand Scholz2, and Klaus Thonke1 — 1Institute of Quantum Matter / Semiconductor Physics Group, University of Ulm, D-89081 Ulm, Germany — 2Institute of Optoelectronics, University of Ulm, D-89081 Ulm, Germany
Semipolar GaN layers grown on foreign substrates typically suffer from a high density of extended defects like threading dislocations and stacking faults. We investigate such (1122)-oriented GaN layers grown by MOVPE on patterned sapphire substrates by spatially and spectrally resolved low-temperature cathodoluminescence. The emission below the excitonic bandgap region is mostly dominated by basal plane stacking faults of I1 type, giving rise to a band at ≈ 3.41 eV, which shifts with the strain and doping level in the layers. We compare experimentally determined transition energies to model calculations based on a wurtzite/cubic/wurtzite GaN quantum well model. Also complete semipolar Ga(In)N based light emitting devices are investigated by spatially correlated cathodoluminescence and electron beam induced current measurements in order to visualize the impact of stacking faults and dislocations on the quality and homogeneity of the quantum wells and on the performance of the pn-junction.