Effects of phosphorus doping in ZnO nanocrystals by metal organic chemical vapor deposition

Abstract

Phosphorus-doped ZnO nanocrystals have been fabricated on Si substrates by metal organic chemical vapor deposition method without using additional thermal activation processes. Single-crystal phosphorus-doped ZnO nanocrystals have the average diameter of 20nm and show preferred orientation with [0001] direction. The acceptor doping resulting in the tuned Fermi level of the ZnO nanocrystals was confirmed by the valence band X-ray photoelectron spectroscopy. The temperature-dependent photoluminescence measurements of undoped and phosphorus-doped ZnO nanocrystals also suggest that phosphorus was doped as an acceptor. The phosphorus-related acceptor state with energy level of 168meV is estimated from the free electron to acceptor transition at 3.27eV.