Structures, growth mechanism and optical properties of Ag-ZnO cored nanotubes

•Ag-ZnO cored nanotube have been firstly synthesized by CVD.•The morphologies and structure of Ag-ZnO cored nanotube are investigated.•The PL properties of Ag-ZnO cored nanotube are investigated.•The mechanism of growth and PL for Ag-ZnO cored nanotube is analyzed. In this paper, Ag-ZnO cored nanotubes were synthesized by a simple chemical vapor deposition method. The morphology and elemental components of the core inside and the nanotube outside of Ag-ZnO cored nanotube were characterized. The X-ray diffraction result showed two series of characteristic peaks, which were connected with hexagonal wurtzite ZnO and face-centered cubic Ag. The growth behaviour of Ag-ZnO cored nanotubes was explained by vapor-liquid-solid mechanism. The optical absorption spectrum showed an absorption peak at 378 nm and the photoluminescence results demonstrated a weak emission peak in the ultraviolet region which was due to the near-band-edge emission as well as three emission peaks in the visible region which were due to the defect level emission.