SKM 2021 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 8: Poster Session II

HL 8.10: Poster

Tuesday, September 28, 2021, 10:00–13:00, P

Spatially resolved multi-probe electrical characterization of GaAs-based nanowire structures — •Juliane Koch¹, Lisa Liborius², Peter Kleinschmidt¹, Werner Prost², and Thomas Hannappel¹ — ¹Fundamentels of energy materials, Ilmenau University of Technology, Germany — ²Components for High Frequency Electronics (BHE), University of Duisburg-Essen, Germany

To achieve high performance optoelectronic devices with III-V semiconductor nanowire (NW) heterostructures sophisticated junctions with controlled properties are required. In order to study microscopic details of the NW structure and its composition, we investigated upright standing p-GaAs/i-GaInP/n-GaInP core-shell-shell NWs on the growth substrates. Cores of the NWs were grown via the vapor-liquid-solid mode followed by epitaxial shell growth in a low-pressure horizontal metalorganic vapor-phase epitaxy reactor. We employ a combination of material-selective wet chemical etching of as-grown coaxial NWs and a multi-tip scanning tunnelling microscope operated as a four-point nano-prober to obtain spatially resolved I-V analysis. These revealed a leakage mechanism causing degraded core-shell pn-junction performance, which is localized at the NW base where a buried contact of the n-GaInP shell to the p-GaAs substrate is formed. Furthermore, the combination of SEM with EDX and XRD measurements reveal the contrast of NW shell and planar layer growth. Our high-end characterization methods enable a direct relation between the NW structures and the electronic properties of as-grown coaxial NWs, which provides precise advice for future NW core-shell pn-junction optimization.