**2.3. Electron microscopy (SEM & TEM) characterization**

All scanning electron microscopy imaging was performed using a field emission scanning electron microscope (ZEISS 1550VP) with an accelerating voltage of 4 kV.

Tranmission electron microscopy was used to further characterize nanowire morphology and microstructure. Isolated nanowires were captured on carbon coated copper grids with 300 mesh size (Ted Pella Inc.) and imaged using a JEOL 2100 (Japan) TEM. Brightfield and darkfield images as well as diffraction patterns were captured. Images were taken on the edges of the nanowires, at the thinner branches (*ɸ* = 20 nm) to ensure transmission of the electron beam through the samples. Diffraction patterns were taken using beam widths smaller than the width of the nanowires, to minimize probability of outside contributions to measured patterns.
