Structure and photoluminescence properties of Si/ZnO coaxial nanowires

초록

Si-core/ZnO-shell coaxial nanorods with a uniform layer thickness were prepared by using a two step process consisting of electroless chemical etching of Si and sputter-deposition of ZnO. TEM analysis and X–ray diffraction (XRD) results indicate that the Si-cores are single crystals with a diamond cubic structure, whereas the ZnO shells are amorphous. The Raman spectrum of Si nanowires shows a symmetric peak at 521 cm-1 compared to a bulk single crystal Si. Photoluminescence (PL) measurement under excitation at 325 nm shows that Si nanowires have a broad PL emission peak centered around at 720 nm, while Si mono oxide has a strong PL at ~ 740 nm and the SiO2 nanowires give a weak PL peak at ~600 nm. The effects of annealing in different atmospheres on the PL properties of the Si nanowires have also been investigated.