CdSe nanowires with controllable growth orientations

Epitaxial growths of CdSe nanowires with controllable orientations by metal organic chemical vapor deposition are obtained. Scanning electron microscopy reveals that they preferred to align along different orientations when grown on different GaAs surfaces. The geometrical relationship between their orientations and the substrates can further be changed by changing the growth temperature. They all grow along the ⟨110⟩ direction of the substrates at 480°C, but along the ⟨111⟩ direction at 500°C. X-ray diffraction and transmission electron microscopy confirm that they are single-crystalline wurtzite structured. Photoluminescence measurements on individual CdSe nanowires reveal their good optical properties.