Regensburg 2016 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 71: Quantum Dots and Wires: Optical Properties

HL 71.11: Talk

Thursday, March 10, 2016, 12:30–12:45, H15

Optical and electrical characterization of single AlGaN/GaN nanowire heterostructures — •Jan Müßener, Pascal Hille, Marius Günther, Daniel Stock, Markus Schäfer, Jörg Schörmann, Jörg Teubert, and Martin Eickhoff — I. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen, Germany

We report on the photoluminescence (PL) characterization of single GaN nanowires (NWs) with embedded AlGaN/GaN heterostructures under application 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). Here we present a controlled modification of the internal fields via externally applied axial voltage on a single NW basis. The NWs were grown by plasma assisted MBE and consist of a single nanodisc (ND) embedded in AlGaN barriers. Single NWs were isolated for µ-PL measurements and electrical contacts for bias application were formed using electron beam lithography. The external electric field leads to a suppression or an enhancement of the QCSE which allows for determining the direction (polarity) and magnitude of the internal field. We also report on analogous measurements on 40-fold AlN/GaN heterostructures embedded in GaN NWs. Their complex bandprofile gives rise to numerous contributions in the PL spectrum originating from direct and indirect ND transition or 2DEG states. As each transition exhibits specific and distinct behavior under external electric field, bias-depended µ-PL allows the assignment of different recombination paths.