| 초록 |
CdSe/ZnS quantum dots with composition gradients were synthesized by a single step synthetic method through a fine control of reactivity difference between group-II precursors (Cd & Zn) and group-VI precursors (Se & S) and were characterized with TEM, ICP-AES, UV-vis., PL and PLE techniques. Synthesized quantum dots have atomic layers with composition (energy) gradients in between CdSe core and ZnS shell which guarantee the relaxation of the strain from lattice mismatch between CdSe core and ZnS shell as well as effective passivation of carriers (electrons and holes), therefore they show high quantum yields (up to 80 %) and stability during surface modification for further applications. Moreover, the optical properties of CdSe/ZnS quantum dots could be tuned (PL max. 510 nm ~ 610 nm) by changing the feed ratio of Cd to Zn and Se to S. Finally, light emitting diodes with CdSe/ZnS quantum dots were demonstrated. |
