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HL: Fachverband Halbleiterphysik

HL 13: Focus Session: GaN-based single photon emitters

HL 13.4: Vortrag

Dienstag, 2. April 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.