Wet chemistry synthesis of ZnO crystals with hexamethylenetetramine(HMTA): Understanding the role of HMTA in the formation of ZnO crystals

ZnO crystals have been prepared via a simple aqueous solution route using zinc acetate-hexamethylenetetramine (HMTA) solution. To understand the role of HMTA in the formation processes of ZnO crystals, concentration measurements of Zn(II) remaining in the solution as well as SEM and XRD analyzes of the solid product have been made at regular intervals. The results demonstrated that the HMTA concentration has determinative effects on the growth rate of obtained ZnO products by controlling the composition of zinc complex species and mediating the transformation rate of building blocks. XRD results revealed the single phase nature with the wurtzite structure of the as prepared ZnO rods. X-ray photoelectron spectroscopy confirmed high purity of the ZnO rods. By varying the concentration of HMTA in the solution, the average size of rods was varied from 5 μm to 10 μm. Photoluminescence spectra indicated that the photoluminescent intensity of the emission peak at 380 nm increase to different degree with increasing HMTA concentration. These results revealed that the concentration of HMTA plays a vital role to control the properties of ZnO crystals.