Exciton radiative lifetime in ZnO quantum dots embedded in SiOx matrix

Using a simple process of the deposition of ZnO thin films on SiOx/Si substrates and subsequent thermal annealing, we fabricated ZnO quantum dots embedded in silicon oxide matrix. The ZnO quantum dots were characterized using transmission electron microscopy, and time-integrated and time-resolved photoluminescences. We measured an exciton radiative lifetime of 65 ps at 4.3 K, which is much shorter than the exciton radiative lifetime of 322 ps in bulk ZnO. The short exciton radiative lifetime can be explained in terms of exciton superradiance. (c) 2006 American Institute of Physics.