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HL: Fachverband Halbleiterphysik

HL 30: Poster: Quantum dots and wires: Preparation, characterization, optical properties and transport

HL 30.26: Poster

Montag, 31. März 2014, 17:00–20:00, P2

InGaN/GaN nanowire heterostructures as optical probes for oxygen-related surface processes — •Pascal Hille¹, Marius Günther¹, Paula Neuderth¹, Pascal Becker¹, Jörg Teubert¹, Jörg Schörmann¹, Matthias Kleine-Boymann², Mariona Coll³, Jordi Arbiol^3,4, Jürgen Janek², Bernd Smarsly², and Martin Eickhoff¹ — ¹I. Physikalisches Institut, Justus-Liebig-Universität Gießen, Germany — ²Physikalisch-Chemisches Institut, Justus-Liebig-Universität Gießen, Germany — ³Ciencia de Materials de Barcelona,CSIC, Campus de la UAB, 08193 Bellaterra, CAT, Spain — ⁴ICREA, Campus de la UAB, 08193 Bellaterra, CAT, Spain

InGaN/GaN nanowire heterostructures (NWHs) show a high sensitivity of their photoluminescence (PL) intensity to the ambient atmosphere rendering them as promising candidates for gas-sensor applications with all-optical readout in the visible spectral range. InGaN/GaN NWHs were grown by plasma-assisted molecular beam epitaxy. Exposure to ppm-concentrations of oxygen leads to a quenching of the PL intensity. This PL response behaviour is investigated for undoped and Ge-doped InGaN/GaN NWHs. A comparison with GaN NWs yields much longer (≈10x) response times of undoped InGaN/GaN NWHs. These time constants, however, can be significantly reduced by Ge-doping. Possible mechanisms will be discussed. Additionally, InGaN/GaN NWHs covered with CeO₂ were investigated in order to assess the potential of NWHs for an optical detection of ad-/desorption processes at catalytic materials.