Dresden 2017 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 41: Nitrides: Preparation

HL 41.5: Talk

Tuesday, March 21, 2017, 12:45–13:00, POT 06

MOVPE-growth of GaN quantum dots on deep UV AlN/AlGaN distributed Bragg reflectors — •Christoph Berger, Hannes Schürmann, Sebastian Metzner, Gordon Schmidt, Jürgen Bläsing, Armin Dadgar, Frank Bertram, Jürgen Christen, and André Strittmatter — Otto-von-Guericke-Universität Magdeburg

GaN quantum dots are potential candidates to realize single photon emitters at room temperature due to their large exciton binding energy and zero-dimensional confinement potential. We observe sharp emission lines from quantum dot states in single GaN islands. These islands are realized by growing a thin GaN layer on an AlN buffer. Applying a subsequent growth interruption allows formation of GaN islands by material desorption. For cavity enhancement of the spontaneous emission, the quantum dots are embedded in an AlN cavity on a highly reflective AlN/AlGaN DBR. Adapted to the QD emission, the DBRs are designed for the deep UV spectral region at wavelengths around 270 nm. Growing 50 pairs of AlN/Al_0.7Ga_0.3N on a thin AlN buffer, crack-formation could be prevented on large wafer areas and reflectivities above 90 % are realized. Structural and optical properties of the DBRs and quantum dots are investigated by XRD, AFM, TEM and cathodoluminescence performed in a SEM and in a transmission electron microscope (STEM-CL).