Regensburg 2019 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 13: Focus Session: GaN-based single photon emitters
HL 13.4: Talk
Tuesday, April 2, 2019, 11:15–11:30, H31
Self-organized GaN quantum dots grown on a wavelength-matched deep UV AlN/AlGaN distributed Bragg reflector — •Hannes Schürmann1, Gordon Schmidt1, Christoph Berger1, Sebastian Metzner1, Peter Veit1, Jürgen Bläsing1, Frank Bertram1, Armin Dadgar1, André Strittmatter1, Jürgen Christen1, Stefan Kalinowski2, Stefan T. Jagsch2, Gordon Callsen2, Markus R. Wagner2, and Axel Hoffmann2 — 1Institute of Physics, Otto-von-Guericke-University Magdeburg — 2Intitute of Solid-State Physics, Technical University Berlin
We present emission properties of self-assembled GaN quantum dots (QDs) in an AlGaN cavity on top of a wavelength-matched deep UV AlN/AlGaN distributed Bragg reflector using cathodoluminescence (CL) experiments directly performed in a scanning transmission (STEM) and a scanning electron microscope (SEM). GaN QD growth results from metalorganic vapor phase epitaxy of a nominally 2 nm thick GaN layer (V/III = 30) directly followed by a growth interruption for 30 s. To avoid a degraded DBR, an Al-concentration of 70 % in the AlGaN layers was chosen regarding the trade-off between the lattice-mismatch of AlN and GaN and its high difference in refractive indices. The obtained sample has the highest reflectivity of 88 % at 272 nm with a stopband width of 9.2 nm. SEM-CL measurements at LHe temperatures demonstrate emission from GaN QDs with an intensity increase at the stopband position of the DBR at 271 nm, thus confirming the successful MOVPE growth of self-organized GaN QDs on top of a highly reflective deep UV DBR.