Fabrication and applications of in-fiber semiconductor and metal microspheres

Abstract

Currently, the synthesis of semiconducting or metal microspheres has occurred via top-down approaches, such as through ball milling or e-beam lithography, or via bottom-up approaches, such as colloidal chemistry. Top-down approaches often generate a wide particle size distribution, while bottom up approaches often involve toxic and sometimes rather expensive precursors to generate the particles. By utilizing a phenomenon known as axial thermal capillary instability, highly homogeneous semiconducting and metal microspheres are able to be generated inside of a silica fiber in a simple, inexpensive, and non-toxic top-down approach. Further applications of these in-fiber microspheres, such as the band gap shift due to localized pressure on Germanium microspheres, and terahertz plasmonic resonances on Silver microspheres, were also studied.