科研之友
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摘要
Steady state and time-resolved optical properties of alloyed core/doped shell MnxZn1-xSe/ZnSe:Mn2+ nanocrystals with x between 0.2 and 1 were studied. The emission from Mn2+ ions at similar to 580 nm is predominant for higher MnSe mole fractions in the core (higher x). At lower fractions, the ZnSe excitonic emission is also present while the Mn2+ emission shifts to similar to 560 nm. The ratio of photoluminescence intensity of these emission bands depends on the composition of the alloyed core. The excited state lifetime of Mn2+ ions is also strongly dependent on the core composition, ranging from 300 mu s for small MnSe mole fractions down to 65 mu s for x=1. This is attributed to the long-range strain caused by a lattice mismatch of more than 4% at the core/shell interface. For x <= 0.6, an additional lifetime, depending on the presence of an extra electron within the nanocrystals, was measured in the hundreds of nanoseconds range. A 4-level dynamic model is proposed to explain this observation.
- 出版日期2017-1
