SKM 2021 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 23: Focus Session: Highlights of Materials Science and Applied Physics III (joint session DS/HL)
HL 23.7: Vortrag
Freitag, 1. Oktober 2021, 12:45–13:00, H1
Impact of electrical current on single GaAs nanowire structure — •Ullrich Pietsch1, Danial Bahrami1, Ali AlHassan1, Arman Davtyan1, Taseer Anjum1, Ren Zhe2, Rainer Timm2, Lutz Geelhaar3, Jesus Herranz3, and Dmiri Novikov4 — 1University of Siegen, Siegen, Germany — 2University of Lund, Lund , Sweden — 3Paul Drude Institute, Berlin, Germany — 4DESY, Hamburg, Germany
The impact of electrical current on the structure of single free-standing Be-doped GaAs nanowires grown on a Si 111 substrate has been investigated by X-ray nano-diffraction before and after the application of an electrical current. The conductivity measurements of same nanowires in their as-grown geometry have been realized via W-probes installed inside a dual beam focused ion beam/scanning electron microscopy chamber. Comparing reciprocal space maps of the 111 Bragg reflection before and after the conductivity measurement, we find a deformation of the hexagonal nanowire cross-section, tilting and bending with respect to the substrate normal. For electrical current densities above 347 A/mm^2, the diffraction pattern was completely distorted. Confirmed by SEM the reconstructed cross-section of the illuminated nanowire shows elongation of two pairs of opposing side facets accompanied by shrinkage of the third pair of facets. To explain our findings, we suggest material melting due to Joule heating during voltage/current application accompanied by anisotropic deformations induced by the W-probe.