摘要
采用反胶束方法制备了ZnS/CdS/ZnS量子点量子阱 ,并对其光谱性质进行了研究。结果表明所制得的量子点量子阱尺寸分布均匀 ,平均粒径为 4 5nm ,发光峰位于 5 1 5nm左右 ,归属于CdS体内的施主 受主对复合。ZnS/CdS/ZnS量子点量子阱中CdS的发光比核 壳结构的ZnS/CdS量子点增强了近四倍 。
With different properties from their bulk materials and potential applications in various fields, semiconductor quantum dots have been researched for several decades. The studying follows three directions: preparing quantum dots of new materials, finding novel preparation method and building up complex heterostructures, such as core-shell structures, quantum dot quantum well structures and so on. Owing to the quantum confinement effect, the rate of radiative transition and the effectiveness of the excitation transfer in quantum dots may be bigger than those in bulk materials, but surface states usually act as luminescence killers. So researching and controlling the surface of quantum dots are important. Because of the good passivation of the shell, some core-shell quantum dots have displayed a quantum yield of 50%. The electronic properties of quantum dot quantum well may be controlled by tuning the thickness and the energetic structures of various layers. The luminescence with high efficiency may be obtained. ZnS has a cubic structure of blende-type very close to that of CdS and a large band gap compared to that of CdS. These are the basic conditions to form a quantum dot quantum well with ZnS and CdS. In this paper, ZnS/CdS/ZnS quantum dot quantum well was prepared by inverted micelles method and was characterized. Dioctylsulfosuccinate sodium salt (AOT) was used as surfactant. The size of the quantum dot quantum well was controlled by the water-to-surfactant mole ratio. The size distribution was narrow and the diameter of the quantum dot quantum well was about 4.5nm, which was consistent with the theoretical calculation. The optical properties were compared with those of core-shell ZnS/CdS quantum dot. Both emissions of the quantum dot quantum well and the core-shell structure were peaked at 515nm which can be attributed to the donor-acceptor recombination in CdS. The luminescence of quantum dot quantum well was stronger than that of the core-shell structure. This can be explained that the ZnS shell of the quantum dot quantum well increased the distance from CdS to surface states, reducing the nonradiative recombination rates. The luminescence decay was measured and the decay curves were fitted by a hyperbolic function. The results indicated that the ZnS shell reduced the relative contribution of the fast process to the overall emission. The luminescence lifetime of quantum dot quantum well was longer than that of the core-shell structure.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2002年第1期81-84,共4页
Chinese Journal of Luminescence
基金
国家重点基础研究发展规划-稀土功能材料的基础研究资助项目 (G19980 6 130 9)
国家自然科学基金资助项目( 1980 40 11)
