ZnO nanorods via spray deposition of solutions containing zinc chloride and thiocarbamide

Abstract

In this work we present the results on formation of ZnO nanorods prepared by spray of aqueous solutions containing ZnCl 2 and thiocarbamide (tu) at different molar ratios. It has been observed that addition of thiocarbamide into the spray solution has great impact on the size, shape and phase composition of the ZnO crystals. Obtained layers were characterized by scanning electron microscopy (SEM) equipped with energy selected backscattered electron detection system (ESB), X-ray diffraction (XRD) and photoluminescence spectroscopy (PL). Small addition of thiocarbamide into ZnCl 2 solution (ZnCl 2:tu = 1:0.25) supports development of significantly thinner ZnO nanorods with higher aspect ratio compared to those obtained from ZnCl 2 solution. Diameter of ZnO rods decreases from 270 to 100 nm and aspect ratio increases from 2.5 to 12 spraying ZnCl 2 and ZnCl 2:tu solutions, respectively. According to XRD, well crystallized (002) orientated pure wurtzite ZnO crystals have been formed. However, tiny 'spot'-like formations of ZnS were detected on the side planes of hexagonal rods prepared from the thiocarbamide containing solutions. Being adsorbed on the side facets of the crystals ZnS inhibits width growth and promotes longitudinal c-axis growth.