Optical Spectroscopy of Sm3+ and Dy3+ Doped ZnO Nanocrystals

Sm³⁺ and Dy³⁺ ions doped hexagonal wurtzite ZnO nanocrystals were fabricated by a sol-gel method. The obtained ZnO nanocrystals were characterized using the X-ray diffraction, transmission electron microscopy, ultraviolet-visible reflectance spectra, and low-temperature luminescence spectroscopy. Intense and well resolved emission lines for Sm³⁺ and Dy³⁺ ions can be achieved via an energy transfer process from ZnO host to the dopants. It was found that the host sensitized emissions were more efficient than that of direct excitation for Sm³⁺ and Dy³⁺ ions. Moreover, multiple sites of Sm³⁺ and Dy³⁺ ions in ZnO nanocrystals were identified based on the low-temperature photoluminescence spectra.