Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 52: Quantum wires: Optical properties (with TT)

HL 52.5: Talk

Tuesday, April 1, 2014, 15:30–15:45, POT 112

Combined optical and electrical characterization of single AlGaN/GaN nanowire heterostructures — •Jan Müßener, Pascal Becker, Svenja van Heesvijk, Markus Schäfer, Pascal Hille, Jörg Schörmann, Jörg Teubert, and Martin Eickhoff — I. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen, Germany

We report on the photoluminescence characterization of single GaN nanowires (NWs) with embedded AlGaN/GaN heterostructures under the influence of an external electric field. Group III-nitrides exhibit strong internal polarization-induced electric fields which influence the optical properties via the quantum confined Stark effect (QCSE). While the presence of the QCSE in NWs has been proven, a controlled modification of the QCSE via external axial electric fields on a single NW basis has not been achieved up to now. NWs were grown along [ 000 1 ] by plasma assisted molecular beam epitaxy on a Si(111) substrate. Their geometry consists of a single ND embedded in AlGaN barriers and surrounded by Ge-doped GaN contacts. We performed numerical simulations of the three dimensional quantum confinement to optimize the sample structure with respect to its opto-electrical properties. Single NWs were isolated for µ-PL measurements and contacts were formed using electron beam lithography to allow application of external axial electric fields. The effect of current induced heating on the low temperature µ-PL spectra was investigated. The application of axial electric fields leads to a suppression or an enhancement of the QCSE which corresponds to the polarity of the NWs.