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HL: Fachverband Halbleiterphysik
HL 31: Poster: Nitrides
HL 31.9: Poster
Montag, 31. März 2014, 17:00–20:00, P2
Structural and luminescence properties of an AlInN/AlGaN based microcavity structure — •Max Trippel, Gordon Schmidt, Peter Veit, Frank Bertram, Christoph Berger, Armin Dadgar, Alois Krost, and Jürgen Christen — Institute of Experimental Physics, Otto-von-Guericke-University, Magdeburg, Germany
Using transmission electron microscopy combined with cathodoluminescence spectroscopy (STEM-CL) we present the spatially resolved optical properties of a microcavity structure (MC) on nanometer scale. In addition, the temperature dependence of the spectral characteristics of the active medium were investigated by photoluminescence.
The MC structure was grown by metal-organic vapor phase epitaxy (MOVPE) on a c-plane sapphire substrate with an op- timized AlGaN buffer structure. A lattice matched 45 pairs Al0.85In0.15N/Al0.2Ga0.8N distributed Bragg reflector (DBR) operates as the bottom mirror. The active medium consists of an InGaN/AlGaN multiple quantum well (MQW) embedded in a λ-cavity.
At 4.2 K the photoluminescence spectrum is dominated by the MQW emission at about 360 nm followed by sideband peaks at 370 nm and 383 nm which are assigned to longitudinal optical phonon replica. The STEM-CL images clearly resolve the complete stacking sequence of the MC structure. Highly spatially resolved STEM-CL linescans reveal a constant MQW peak position along growth direction indicating spec- trally identical QWs. Within the DBR stack, we observe an emission at about 335 nm originating from the AlGaN layers.