Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 24: Focus Session: Functional Semiconductor Nanowires II (organized by HL)
TT 24.3: Vortrag
Montag, 16. März 2015, 15:45–16:00, EW 201
Time-resolved optical spectroscopy of InGaN/GaN 3D-LEDs — •Linus Krieg1, Johannes Dühn1, Kathrin Sebald1, Jürgen Gutowski1, Christian Tessarek2, Martin Heilmann2, Silke Christiansen2, and Tobias Voss3 — 1Institute of Solid State Physics, University of Bremen — 2Max-Planck-Institute for the Science of Light, Erlangen — 3Institute of Semiconductor Technology, TU Braunschweig
GaN is an efficient and widely established material for optoelectronic devices, especially light-emitting diodes (LEDs). Core-shell InGaN/GaN nano- and microrod structures are supposed to further improve the efficiency and spectral range of conventional GaN-based structures leading to LEDs in the green-to-ultraviolet spectral region. Using optical spectroscopy, we perform a characterisation of self-assembled GaN micro- and nanorods with an embedded threefold InGaN quantum well (QW). The GaN rod structures were grown in a vapour-liquid-solid (VLS) growth mode. Afterwards, InGaN QWs were deposited around the rods. After using time-integrated photoluminescence measurements to analyse the concentration and homogeneity of the indium, we focus on time-resolved optical spectroscopy and determine the temperature dependent decay times. The tip of the micro- and nanorods is partly covered with a GaN pyramid. By using micro-PL measurements, we can determine the InGaN distribution on the tip as well as the impact of the GaN pyramid. Our results show a clear decrease of decay time with rising temperature and a spectral shift of the luminescence originating from the tip.