ZnO films were deposited by atmospheric pressure metal-organic chemical vapor deposition (AP-MOCVD) from diethylzine (DEZ)-83% n-hexane and H2O. Analysis of the film growth rate on tubular quartz glass substrates revealed that the growth process is limited by the gas-phase diffusion of growth species in the temperature range of 400-600 degrees C. From the experimentally measured diffusivites and by correlating with the Chapman-Enskog equation, we obtained the effective molecular size of the growth species-to be about 0.5 nm. The growth rate data at 650 degrees C indicates that the growth rate is limited by gas-phase reaction with a rate constant, k(g) of 60 s(-1). At 700-750 degrees C, the film growth was gas-phase diffusion controlled. The molecular size was about 0.9 nm at 700 degrees C, and decreased to about 0.6 nm at 7.50 degrees C. (C) 2008 Elsevier B.V. All rights reserved.