Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 19: Nitrides: Devices

HL 19.5: Talk

Monday, March 31, 2014, 16:00–16:15, POT 151

Characteristics of sub-300 nm AlGaN multiple quantum well lasers grown on epitaxially laterally overgrown AlN/sapphire substrates — •Martin Martens¹, Peter Schneider¹, Frank Mehnke¹, Christian Kuhn¹, Christoph Reich¹, Viola Kueller², Arne Knauer², Carsten Netzel², Jens Rass^1,2, Tim Wernicke¹, Markus Weyers², and Michael Kneissl^1,2 — ¹Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, 10623 Berlin, Germany — ²Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany

We have investigated the characteristics of AlGaN-based multiple quantum well (MQW) lasers emitting in the UV-B to UV-C spectral range. The laser heterostructures were grown by metal organic vapor phase epitaxy in [0001] direction on low defect density epitaxially laterally overgrown AlN/sapphire substrates. The separate confinement heterostructures consist of Al_xGa_(1−x)N/Al_0.70Ga_0.30N MQWs and Al_0.70Ga_0.30N/Al_0.80Ga_0.20N waveguiding heterostructures. Opitcally pumped lasing was obtained in a wavelength range between 272 nm and 293 nm with threshold energy densities down to 15 mJ/cm² for resonant pumping of the MQW. Laser emission was transverse electric polarized independent of the wavelength. The variable stripe length method was applied to determine the gain spectra of different laser heterostructures. The influence of emission wavelength and sample morphology on the laser threshold and gain characteristics will be discussed.