Synthesis and Optical Characterization of ZnO Quantum Dots and Nanorods

ZnO quantum dots were synthesized via precipitation using millimolar solutions of zinc acetate and sodium hydroxide in methanol. The synthesized quantum dots were characterized via absorption and fluorescence measurements. The onset of absorption observed at a lower wavelength of ∼350 nm as compared to bulk (380 nm) indicates an increase in the band gap through quantum confinement and confirms the presence of quantum dots. In order to calculate the size and distribution of ZnO quantum dots, fluorescence measurements were made. The synthesized quantum dots were drop casted on gold coated silicon substrates and were used as seeds to grow nanorods by using aqueous solutions of zinc nitrate (hexahydrate) and hexamine. The FESEM micrographs revealed good quality hexagonal shaped nanorods with a relatively uniform diameter of ∼75 nm.