Self-organized ZnO quantum dots on SiO2/Si substrates by metalorganic chemical vapor deposition

Abstract

ZnO quantum dots (QDs) were fabricated on SiO2/Si substrates by metalorganic chemical vapor deposition. The densities and sizes of dots were investigated by atomic force microscopy. Photoluminescence at 10 K showed the broad spectra with band tails up to about 3.55 and 3.65 eV for the as-grown and the annealed ZnO QDs, respectively, which were located at the higher energy with respect to the free exciton emission of the ZnO thin film located at about 3.377 eV. These results indicate that the broad emission band results from the quantum size effect, reflecting the dot size inhomogeneity.