Department of Physics and Astronomy, University of Alabama in Huntsville, Huntsville, AL 35899, United States of America.
Nanotechnology. 2018 Jan 5;29(1):015402. doi: 10.1088/1361-6528/aa9a1c.
We demonstrate that a metal-oxide plasmonic metafilm consisting of a Si/Al oxide junction in the vicinity of a thin gold layer can quarantine excitons in colloidal semiconductor quantum dots against their defect environments. This process happens while the plasmon fields of the gold layer enhance spontaneous emission decay rates of the quantum dots. We study the emission dynamics of such quantum dots when the distance between the Si/Al oxide junction and the gold thin layer is varied. The results show that for distances less than a critical value the lifetime of the quantum dots can be elongated while they experience intense plasmon fields. This suggests that the metal-oxide metafilm can keep photo-excited electrons in the cores of the quantum dots, suppressing their migration to the surface defect sites. This leads to suppression of Auger recombination, offering quantum dot super-emitters with emission that is enhanced not only by the plasmon fields (Purcell effect), but also by strong suppression of the non-radiative decay caused by the defect sites.
我们证明，由附近的薄金层中的 Si/Al 氧化物结组成的金属氧化物等离子体超材料可以将胶体半导体量子点中的激子与它们的缺陷环境隔离开来。这个过程发生在金层的等离子体场增强量子点的自发发射衰减率的同时。当 Si/Al 氧化物结和金薄层之间的距离变化时，我们研究了这种量子点的发射动力学。结果表明，对于小于临界值的距离，量子点的寿命可以延长，同时它们经历强烈的等离子体场。这表明金属氧化物超材料可以将光激发的电子保留在量子点的核心中，抑制它们向表面缺陷位点的迁移。这导致了俄歇复合的抑制，为量子点超发射器提供了不仅由等离子体场（Purcell 效应）增强的发射，而且还由缺陷位点引起的非辐射衰减的强烈抑制。
