Well-aligned ZnO nanowires grown on Si substrate via metal–organic chemical vapor deposition

ZnO nanowires were grown on silicon substrate by metal–organic chemical vapor deposition (MOCVD) without catalysts. The scanning electron microscopy (SEM) observations along with X-ray diffraction (XRD) results suggest that the ZnO nanowires are single crystals vertically well-aligned to silicon substrate. Room-temperature photoluminescence (PL) measurement reveals strong UV emission and weak green emission, which demonstrates that the nanowires are of good optical properties. The mechanism of the catalyst-free growth of ZnO nanowires on silicon substrate is proposed.