ZnO nanoparticles as small as 80 nm were successfully synthesized using a modified vapor phase transport (VPT) process at substrate temperatures as low as 222 degrees C Particle size distribution and morphology were characterized by scanning electron microscopy and atomic force microscopy Energy dispersive X-ray spectroscopy and X-ray diffraction indicate the synthesis of high quality crystalline ZnO structures Low temperature (4 2 K) photoluminescence (PL) spectroscopy was used to characterize the optical quality of the nanoparticles Ultraviolet emission and a nanostructure specific feature at 3 366 eV are strong in the PL spectra The 3 366 eV feature is observed to predominate the spectrum with decrease in particle size This size effect corroborates the luminescence as a nanostructure-specific surface related exciton feature as previously speculated in the literature In addition self-assembled ZnO mesoparticles ( > 100 nm) were realized by increasing the growth time Low growth temperatures of the particles allow for their potential utilization in flexible organic hybrid optoelectronics However this work focuses mainly on the modified synthesis and optical characterization of nanoparticles (C) 2010 Elsevier B V All rights reserved