Abstract
Highly faceted ZnO rods with 18 side surfaces were synthesized. Their optical properties were characterized by variable temperature photoluminescence, time-resolved photoluminescence, and time-integrated photoluminescence. Low-temperature photoluminescence is dominated by a narrow donor bound exciton peak, while at room temperature ultraviolet emission and green emission can be observed. In spite of the presence of the defect emission, the samples have excellent crystal quality based on the long lifetime of spontaneous emission, with the time constants of biexponential decay equal to 116ps and 1.2ns. With increasing pump fluence, stimulated emissions due to excitonic and electron-hole plasma effects were observed. The lasing dynamics in both emission regimes is discussed. © 2006 American Institute of Physics.