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HL: Fachverband Halbleiterphysik

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

HL 13.3: Hauptvortrag

Dienstag, 2. April 2019, 10:30–11:00, H31

Growth of desorption-induced GaN quantum-dots — •Christoph Berger¹, Gordon Schmidt¹, Hannes Schürmann¹, Sebastian Metzner¹, Peter Veit¹, Jürgen Bläsing¹, Frank Bertram¹, Armin Dadgar¹, Jürgen Christen¹, André Strittmatter¹, Stefan Kalinoswki², Stefan T. Jagsch², Gordon Callsen², Markus R. Wagner², and Axel Hoffmann² — ¹Institute of Physics, Otto-von-Guericke-University Magdeburg — ²Institute of Solid State Physics, Technical University Berlin

We studied the MOVPE-growth of thin GaN films on top of AlN/sapphire-templates. After the deposition of a few monolayers GaN at 960°C, a growth interruption (GRI) with durations between 0 s and 60 s without ammonia supply was applied to allow for quantum dot formation. Each quantum dot (QD) structure was capped with AlN grown at 1195°C. Without a GRI, a continuous GaN layer with additional hexagonally-shaped truncated pyramids forms. On the other hand growth interruptions lead to desorption of GaN resulting in smaller islands without definite form located in close vicinity to threading dislocations. Ultra narrow line widths in the spectral range from 220 nm to 310 nm are observed from these islands and single photon emission is verified by Hanbury Brown-Twiss experiments. Aiming for efficient single photon sources realized as resonant cavity structures, such quantum dots were also grown on deep-UV AlGaN/AlN distributed Bragg reflectors with maximum reflectivities of 98 %.