In this study, vertically aligned ZnO nanowires were grown by metal organic chemical vapor deposition (MOCVD) method. The growth direction of vertically aligned nanowires was along c-axis. For monolithic integration, vertically aligned ZnO nanowires were grown on AlN/Si substrates with a higher aspect ratio in comparison to those on bare silicon substrates. In a separate experiment, micro-patterning of the nanowires was obtained by lift-off technique, where BaF2 film was used as a sacrificial layer. ZnO nanowires based UV detectors were fabricated using silicon microchannel. Nanowires with higher aspect ratio exhibited the highest on-off current ratio and less photoresponse time.