Institute of Photonics and Optoelectronics, and Department of Electrical Engineering, National Taiwan University, 1, Roosevelt Road, Section 4, Taipei 10617, Taiwan.
Nanotechnology. 2011 Nov 25;22(47):475201. doi: 10.1088/0957-4484/22/47/475201. Epub 2011 Nov 2.
Based on the fabrication of Ag nanoparticles (NPs) with controlled geometry and surface density on an InGaN/GaN quantum well (QW) epitaxial structure, which contains indium-rich nano-clusters for producing localized states and free-carrier (delocalized) states in the QWs, and the characterization of their localized surface plasmon (LSP) coupling behavior with the carriers in the QWs, the interplay behavior of LSP coupling with carrier delocalization in the QWs is demonstrated. By using the polystyrene nanosphere lithography technique with an appropriate nanosphere size and adjusting the post-fabrication thermal annealing condition, the induced LSP resonance wavelength of the fabricated Ag NPs on the QW sample can match the QW emission wavelength for generating the coherent coupling between the carriers in the QWs and the induced LSP. The coupling leads to the enhancement of radiative recombination rate in the QWs and results in increased photoluminescence (PL) intensity, red-shifted PL spectrum, reduced PL decay time, and enhanced internal quantum efficiency. It is found that the observed effects are mainly due to the LSP coupling with the delocalized carriers in the QWs.
基于在含有富铟纳米团簇的 InGaN/GaN 量子阱（QW）外延结构上制备具有受控几何形状和表面密度的 Ag 纳米颗粒（NPs），在 QW 中产生局域态和自由载流子（离域）态，并对其局域表面等离子体（LSP）与 QW 中的载流子的耦合行为进行了表征，证明了 LSP 与 QW 中载流子离域的相互作用行为。通过使用具有适当纳米球尺寸的聚苯乙烯纳米球光刻技术，并调整后制造热退火条件，在 QW 样品上制备的 Ag NPs 的诱导 LSP 共振波长可以与 QW 发射波长匹配，从而产生 QWs 中的载流子和诱导 LSP 之间的相干耦合。这种耦合导致 QWs 中的辐射复合速率增强，从而导致光致发光（PL）强度增加、PL 光谱红移、PL 衰减时间减少和内部量子效率提高。结果表明，观察到的效应主要归因于 LSP 与 QWs 中离域载流子的耦合。
