Experimental approaches using an open-plate reactor were proposed to investigate the thermal decomposition and deposition processes of solution droplets sprayed over a heated horizontal plate. The temperature-dependent flow condition of the carrier gas may influence the properties of incoming sprayed aerosols. Zinc oxide (ZnO) particle layers were synthesized by spraying zinc acetate solution to the plate with deposition angle of 45 degrees. The prepared particle layers and a numerical simulation verified the presence of thermally generated convection and fluid instability. Correlation between the size and morphology of deposited aerosols and the dynamical condition due to temperature distribution above the plate has been analyzed. A short distance (2 cm) between the nozzle and the plate will prepare finer (nanometer-scaled) ZnO particle layers. ZnO with higher crystallinity can be prepared using one-step route (directly spraying at 450 degrees C) compared with those of two-step heating procedures (150 degrees C - spraying then 450 degrees C - re-heating in 1 h), which consume higher energy. (C) 2017 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.