Properties of ZnO nanofilms formed at solution interfaces by nanoparticle oriention arrangement

ZnO nanoparticles with the diameter of 11-33 nm were grown by decomposing a mixture of Zn(CH3COO)2 x 2H2O with NaCl and Li2CO3. Compact ZnO nanofilms were fabricated with the as-grown nanoparticles at the interfaces of the polar and non-polar solutions. The nanofilm properties were characterized by X-ray diffraction, scanning electron microscope, photoluminescence spectroscope and Raman spectroscope. Effects of the nanoparticle size on the nanofilm properties were studied. The nanoparticles with smaller sizes would align preferentially along [001] orientation during forming a film at an interface of two kinds of solutions. The nanofilm photoluminescence and Raman vibration are very sensitive to the sizes of the nanoparticles that form the nanofilms. 1LO vibration is enhanced in the nanofilms composed of nanoparticles with sizes smaller than 20 nm. The enhancement is attributed to the high density of deep level defects.