Growth, structural and vibrating properties of CdSe-Ge, CdSe-Ge-CdSe, CdSe-Ge/Ge, Ge-GeSe heterostructure nanowires and GeSe nanobelts

CdSe-Ge, CdSe-Ge-CdSe heterostructure nanowires, CdSe-Ge biaxial nanowire core/polycrystalline Ge sheath heterostructures, Ge-GeSe biaxial nanowires and GeSe nanobelts were grown via a simple one-step thermal evaporation of different molar ratios of CdSe and Ge, respectively. The CdSe and Ge subnanowires in CdSe-Ge biaxial nanowires (or triaxial nanowires) and the Ge and GeSe subnanowires in Ge-GeSe biaxial nanowires are single crystalline. A good epitaxial relationship exists in the interface between CdSe and Ge in CdSe-Ge biaxial nanowires and in the interface between Ge and GeSe in Ge-GeSe biaxial nanowires. Two sides of CdSe subnanowires in the CdSe-Ge-CdSe triaxial nanowire have an obvious differential in microstructure is just induced by the view angle. A structural model for the crystallographic relationship between CdSe and Ge in CdSe-Ge biaxial nanowires is given. The possible growth mechanism of CdSe-Ge based heterostructure nanowires is proposed as the co-growth mechanism. The vibrating properties of CdSe-Ge based heterostructure nanowires were investigated by micro-Raman spectroscopy. We observe a LO mode of CdSe, a LO (TO) mode of Ge and a LO and TO mode of GeSe in the five different nanostructures have the different wave-number shift in comparison with that of the responding bulk counterpart, respectively.