科研之友
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摘要
We have studied theoretically the size dependent excitonic properties in core-shell shaped II-VI quantum dot nanocrystals. We have considered three typical heterostructures; CdS/ZnS, CdSe/ZnS and CdTe/ZnS. Utilizing the effective-mass theory, we have calculated the electronic and excitonic energy levels, by solving a three dimensional Schrodinger equation. It is shown that the ground state exciton energy changes significantly when varying the nanocrystal size. Our calculations revealed also that the binding energy as well as the exciton oscillator strength, which is a measure of the integrated intensity of excitonic transitions, appear to be strongly sensitive to the NC size. As a consequence, the optical and electronic properties are determined and can be controlled by the size of the dot. These results could be very helpful as are closely related to experiments performed on these types of nanoparticles, such as improving the stability and efficiency of semiconductor quantum dot luminescence that is considered as a critical aspect.
- 出版日期2009-10
