Quantum confinement in Volmer-Weber-type self-assembled ZnO nanocrystals

We have studied the quantum confinement effect on Volmer-Weber-type self-assembled ZnO nanocrystals. Volmer-Weber-type self-assembled ZnO nanocrystals were grown on the Pt(111) substrate by using a rf-magnetron sputtering method and were confirmed by the Auger electron spectroscopy. The free exciton transition energies of 57-, 38-, and 24- nm- size nanocrystals were found to be roughly 3.298, 3.311, and 3.337 eV, respectively, by photoluminescence measurements at room temperature. The blueshift of the photoluminescence peak energy of ZnO nanocrystals of 24 nm in diameter roughly varied by 40 meV compared to bulk ZnO. (c) 2005 American Institute of Physics.