Fig. 3

Capillary breakup: a (I) Fiber section showing Si spheres formed through capillary breakup (scale bar 0.5 μm). a (II) Single sphere image depicting shape quality (scale bar 100 nm), from Gumennik et al. [26]. b (I) Example of metal-semiconductor-metal photodetecting device in a single silica fiber before b (I) and after b (II) breakup process, from Wei et al. [54]. c (I) Breakup of a double-core fiber into bi-spherical clusters (scale bar 100 μm), from Gumennik et al. [26]. c (II) Schematic representation of the process shown in c (I), with p- and n-type cores shown in blue and red, respectively