Tailoring hot-exciton emission and lifetimes in semiconducting nanowires via whispering-gallery nanocavity plasmons
Tailoring hot-exciton emission and lifetimes in semiconducting nanowires via whispering-gallery nanocavity plasmons
复制标题
DOI：
10.1038/nmat3067
复制
发表时间：
2011-09-01
期刊：
影响因子：
41.2
通讯作者：
Agarwal, Ritesh
中科院分区：
文献类型：
--
作者：
Cho, Chang-Hee;Aspetti, Carlos O.;Agarwal, Ritesh
与表面等离子体耦合的光发射器的辐射性质的操纵对于工程设计新的纳米级光电器件（包括激光器、检测器和单光子发射器）是重要的（1-8）。然而，到目前为止，半导体和分子系统中激发态的辐射率仅适度增强，通常为10-50倍，主要由热化激子产生发射（2，6，9 -11）。在这里，我们展示了占主导地位的热激子发射的产生，也就是说，从非热化激子的发光增强由共振回音壁等离子体纳米腔的CdS-SiO2-Ag核壳纳米线设备的高度集中的电磁场。通过调整等离子体腔尺寸以匹配回音壁共振，可以实现从热化激子到热激子发射的几乎完全的转变，这反映了>10（3）和亚皮秒寿命的异常高的辐射速率增强。核-壳等离子体纳米线是研究和控制纳米尺度强等离子体激子相互作用的理想试验平台，为超快纳米光子器件的应用开辟了新的途径。
The manipulation of radiative properties of light emitters coupled with surface plasmons is important for engineering new nanoscale optoelectronic devices, including lasers, detectors and single photon emitters(1-8). However, so far the radiative rates of excited states in semiconductors and molecular systems have been enhanced only moderately, typically by a factor of 10-50, producing emission mostly from thermalized excitons(2,6,9-11). Here, we show the generation of dominant hot-exciton emission, that is, luminescence from non-thermalized excitons that are enhanced by the highly concentrated electromagnetic fields supported by the resonant whispering-gallery plasmonic nanocavities of CdS-SiO2-Ag core-shell nanowire devices. By tuning the plasmonic cavity size to match the whispering-gallery resonances, an almost complete transition from thermalized exciton to hot-exciton emission can be achieved, which reflects exceptionally high radiative rate enhancement of >10(3) and sub-picosecond lifetimes. Core-shell plasmonic nanowires are an ideal test bed for studying and controlling strong plasmon-exciton interaction at the nanoscale and opens new avenues for applications in ultrafast nanophotonic devices.