Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 44: Poster Session: Quantum Dots and Wires - Transport & Optical Properties

HL 44.22: Poster

Tuesday, March 27, 2012, 09:30–12:30, Poster D

Carrier confinement in GaN/AlGaN nanowire heterostructures — •Jörg Teubert¹, Florian Furtmayr¹, Pascal Becker¹, Jan Müßener¹, Alexey Chernikov³, Sören Schäfer³, Sangam Chatterjee³, Jordi Arbiol², and Martin Eickhoff¹ — ¹I. Physikalisches Institut, Justus-Liebig-Universität Gießen, Germany — ²ICREA and Institut de Ciencia de Materials de Barcelona, Spain — ³Faculty of Physics and Materials Science Center, Philipps Universität Marburg, Germany

GaN nanowires (NWs) can be grown by molecular beam epitaxy using a catalyst free growth process. Due to their low density of defects group III-nitride NWs present a promising approach for the realization of improved nano- or optoelectronic devices. With this respect, the realization of heterostructures embedded in NWs is of major importance. We analyzed the three dimensional carrier confinement in GaN nanodiscs (NDs) embedded in Al_xGa_1−xN/GaN NWs and its effect on their photoluminescence (PL) properties for Al concentrations in the barriers (x_Al) between x_Al = 0.04 and 1 and for different ND heights. Structural analysis by high resolution transmission electron microscopy reveals the presence of a lateral AlGaN shell. In order to obtain a deeper understanding of the relevant effects we performed three dimensional numerical simulations of the confinement which show that the effects of the AlGaN shell have to be considered to explain the observed dependence of the emission energy on x_Al. Effects of axial and radial internal electric fields have been investigated using NW samples with different ND thickness.