Reduction of nonradiative recombination center for ZnO films grown under Zn-rich conditions by metal organic chemical vapor deposition

摘要

ZnO films were grown by metalorganic chemical vapor deposition using the repeated temperature modulation in an H_2 ambient. The crystalline quality, as defined by the full-width at half-maximum of the ω (1011) reflection, was found to be correlated with the photoluminescence (PL) lifetime at 300 K. The fine structure of the PL spectra for the samples grown under Zn-rich condition at 8 K indicated the higher order (n=2) structure of free exciton A, two electron satellites and phonon-replicas. The internal quantum efficiency and the PL lifetime at 300 K were 5.5% and 2.6 ns, respectively, indicating a reduction in Zn vacancies in the ZnO films.