Light-emitting diodes fabricated from small-size ZnO quantum dots

Zinc oxide (ZnO) quantum dots (QDs) have been fabricated. High-resolution transmission electron microscopy shows that the ZnO QDs have a narrow size distribution, and are highly crystallized with wurtzite structure. Light-emitting diodes have been constructed by employing the QDs as active layers. Intense near-band-edge emissions have been observed from the diodes, which show a noticeable blue-shift compared with the emission of a similar diode employing ZnO film as an active layer, which is demonstrated to come from the quantum size effect of the QDs due to their small size. (C) 2012 Elsevier B.V. All rights reserved.