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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: Talk

Friday, October 1, 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.