Berlin 2008 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 6: Semiconductor Nanophotonics: Materials, Models, Devices - High Speed Photonics

DS 6.3: Vortrag

Montag, 25. Februar 2008, 10:30–10:45, H 2032

1500 nm MOVPE-Grown InP-Based Quantum Dot (QD) Emitters — •Harald Künzel, Dieter Franke, Peter Harde, Jochen Kreißl, and Martin Möhrle — Fraunhofer Institut für Nachrichtentechnik HHI, Einsteinufer 37, D-10587 Berlin

A present R&D task is to transfer the QD technology to InP-based GaInAsP materials for applications in the 1550 nm regime and beyond. Real QDs as successfully presently only achieved by conventional MOVPE have become one of the key techniques recently for emitter applications. The Stranski-Krastanow growth mode allows for the realisation of high densities of quite homogeneous QDs which in combination with stacking of uncoupled QD layers is a prerequisite to form the gain region in photonic devices. Furthermore, during implementation of such structures as active layers in laser structures thermal stability of the QDs during growth of the upper claddings was found to be severe problem most probably due to movement of In towards the QDs resulting in a marked blue-shift of the emission. This shift was systematically investigated using thermal treatment to simulate cladding growth. The strong dependence of the blue-shift of the QD emission on growth temperature is attributed to defects being incorporated during QD deposition. A careful adjustment of deposition conditions for stable emission and high QD density forms the basis for the fabrication of lasers with characteristics which as a whole are among the best achieved so far. Recent advances in lasers and epitaxial regrowth for BH-type optical amplifiers will be presented.