Dresden 2011 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 65: Nitrides: AlGaN

HL 65.2: Talk

Wednesday, March 16, 2011, 17:15–17:30, POT 51

Growth and characterization of highly reflective AlInN/AlGaN Bragg reflectors — •Christoph Berger, Jürgen Bläsing, Armin Dadgar, Thomas Hempel, Jürgen Christen, and Alois Krost — Otto-von-Guericke-Universität Magdeburg, Deutschland

We report on the growth of distributed Bragg reflectors (DBRs) with up to 40 periods based on lattice matched Al_0.85In_0.15N/Al_0.2Ga_0.8N layers. Using an Al_0.2Ga_0.8N buffer, which is directly grown on the c-plane sapphire substrate, stress relief through crack formation or by relaxation processes can be prevented, which is confirmed by Nomarski microscopy and X-ray reciprocal space maps. The structures exhibit homogenous layer thicknesses and sharp interfaces, as revealed by FE-SEM images, in-situ reflectivity measurements and high resolution X-ray diffraction. These properties allow the growth of DBRs with reflectivities higher than 99 % at a wavelength of ≈360 nm. Such mirrors are very promising for the use in high Q-factor microcavities for the subsequent realization of GaN-based VCSELs or the observation of strong exciton-photon coupling.