We report on the growth of ZnO nanostructures in different gas ambient (Ar and N-2) using pulsed laser deposition technique. Despite the similar growth temperature, use of N-2 ambient gas resulted in well-aligned nanorods with flat surface at the tip, whereas, nanorods grown with Ar ambient exhibited tapered tips. The Nanorods grown under N-2 ambient exhibited additional Raman modes corresponding to N induced zinc interstitials. The nanorods are c-axis oriented and highly epitaxial in nature. Photoluminescence spectroscopy reveals that the UV emission can be significantly enhanced by 10 times for the nanorods grown under Ar ambient. The enhanced UV emission is attributed to the reduction in polarization electric field along the c-axis. n-ZnO nanorods/p-Si heterojunction showed rectifying I-V characteristics with a turn of voltage of 3.4V. (C) 2017 Elsevier B.V. All rights reserved.