Synthesis and optical characterizations of chain-like Si@SiSe2 nanowire heterostructures

A new type of chain-like Si@ SiSe2 nanowire heterostructures has been successfully synthesized via a one-step Au-catalyzed chemical vapor deposition (CVD) route. The composition and microstructure of the achieved structures were investigated by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscope (TEM) and micro-Raman spectroscopy. Optical characterization was investigated using a confocal photoluminescent system with an Ar+ laser (488 nm) as the excitation source. The results reveal that these chain-like structures emit pronounced and broadband red light, even visible with the naked eye at room temperature. A self-organization model was proposed to illustrate the formation of these heterostructures, and the photoluminescent properties were discussed in detail. These new Si-based nanostructures may be helpful for further study of the basic physical properties of SiSe2 and will find interesting applications in nanophotonic technologies and devices.