On the origin of suppression of free exciton no-phonon emission in ZnO tetrapods

Temperature dependent photoluminescence and cathodoluminescence (CL) spectroscopies are employed to investigate free exciton (FX) emissions in ZnO tetrapods. The intensity of the no-phonon line is found to be largely suppressed as compared with longitudinal optical phonon assisted transitions, in sharp contrast to bulk ZnO. From spatially resolved CL studies, this suppression is shown to strongly depend on structural morphology of the ZnO tetrapods and becomes most significant within areas with faceted surfaces. A model based on reabsorption due to multiple internal reflections in the vicinity of the FX resonance is suggested to account for the observed effect.Original Publication: Shula Chen, Sun Kyun Lee, Weimin Chen, H X Dong, L Sun, Z H Chen and Irina Buyanova, On the origin of suppression of free exciton no-phonon emission in ZnO tetrapods, 2010, APPLIED PHYSICS LETTERS, (96), 3, 033108. http://dx.doi.org/10.1063/1.3292027 Copyright: American Institute of Physics http://www.aip.org