Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 54: Optical Properties

HL 54.3: Vortrag

Mittwoch, 28. März 2012, 11:30–11:45, EW 203

Microscopic optical investigation of a GaN based semi microcavity for fabricating a full resonant hybrid structure — •A. Franke, B. Bastek, O. August, S. Petzold, S. Sterling, T. Hempel, P. Veit, J. Christen, P. Moser, C. Berger, J. Bläsing, A. Dadgar, and A. Krost — Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany

For the investigation of strong coupling between an excitonic and a cavity mode we fabricated a hybrid GaN based microcavity (MC). The sample consists of an epitaxially grown bottom DBR of 40.5 lattice matched AlInN/GaN λ/4 layer pairs and a 3λ/2 cavity containing a fivefold InGaN/GaN multi quantum well. First the microscopic reflectivity and emission properties of the MC structure without top DBR were investigated across the full 2” wafer size at identical positions on the sample. The center wavelength of the bottom DBR stop band exhibits a red shift of 8 nm from the center to the middle part of the wafer. A similar behavior is observed for the MQW emission wavelength. Resonance, i.e., a match of both wavelengths, is found at a circular region near the center part of the wafer. Full resonance of the sample was achieved by dry etching of the cavity layer to the optimal optical cavity thickness of 3λ/2. No influence of the etching process on the emission properties of the active layer was observed. The microcavity was completed by depositing an eightfold dielectric Ta₂O₅/SiO₂ top DBR. Local photoluminescence spectra show a strong narrowing of emission peaks compared to the half MC.