UV-C Lasing From AlGaN Multiple Quantum Wells on Different Types of AlN/Sapphire Templates
J. Jeschke1, M. Martens2, A. Knauer1, V. Kueller1, U. Zeimer1, C. Netzel1, C. Kuhn2, F. Krueger2, C. Reich2, T. Wernicke2, M. Kneissl1,2, and M. Weyers1
Published in:
IEEE Photonics Technol. Lett., vol. 27, no. 18, pp. 1969-1972 (2015).
Abstract:
AlGaN multiple quantum well lasers for optical pumping have been grown by metal-organic vapor phase epitaxy on high and low dislocation density AlN/sapphire templates. Lasers on planar templates exhibited high dislocation densities and high V-pit densities, but a smooth surface morphology leading to inefficient, but laterally very homogeneous optical emission. Lasing was not observed when optically pumped with up to 50 MW/cm2. Epitaxially laterally overgrown templates on patterned sapphire showed much lower dislocation densities, but also step bunching on the surface. This resulted in good photoluminescence efficiencies of up to 20%, but also in a higher lateral inhomogeneity of the emission. Lasers on these templates exhibited lasing at ∼240 nm with low full-width at half-maximum of 1 nm and threshold power densities of 11-15 MW/cm2.
1 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany
2 Institute of Solid State Physics, Technische Universität Berlin, 10623 Berlin, Germany
Index Terms:
AlGaN, epitaxial lateral overgrowth, lasers, sapphire substrates, ultraviolet.
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