Effects of N doping on zinc oxide (ZnO) thin films by metal organic vapor phase epitaxy (MOVPE) using diethyl zinc (DEZn) and O-2 precursors and NH3 as the doping source have been studied. N-doped ZnO thin films were deposited on c-plane sapphire substrates with NH3 flow rates from 0.2% to 4% during growth. Highly resistive ZnO thin films with p-type carrier concentrations of 4.24 x 10(14) cm(-3) and mobility of 16.55 cm(2)/Vs were obtained. Resistivity for the as-grown films on the order of 2.3 x 10(6) Omega cm was observed. The PL results of the N-doped ZnO show suppression of the band-edge luminescence and two broad peaks centered at 480 and 600 nm attributable to deep N acceptor luminescence were seen, Rapid thermal annealing at 800 degrees C in N-2 ambient turned all the N-doped ZnO films, irrespective of doping concentration, to highly conductive n-type with carrier concentration on the order of 5.92 x 10(18) cm(-3), mobility on the order of 34.91 cm(2)/Vs and resistivity of 0.09 Omega cm. (C) 2008 Elsevier B.V. All rights reserved.