Wang Hui, An Zhenghua, Ren Qijun, Wang Hengliang, Mao Feilong, Chen Zhanghai, Shen Xuechu
Laboratory of Advanced Materials, Fudan University, Song-Hu Road 2205#, Shanghai 200433, China.
J Nanosci Nanotechnol. 2011 Dec;11(12):10886-90. doi: 10.1166/jnn.2011.4090.
The porous silicon (PS) samples, decorated by Au nanoparticles (NPs) possessing localized-surface-plasmon (LSP) resonance, are prepared by the conventional anodization method. Photoluminescence (PL) is studied systematically, in particular, its dependence on the excitation power. It is found that undecorated PS samples exhibit a saturation behavior in PL intensity with increasing the pumping laser power, while the luminescence of Au-decorated PS hybrid samples have a purely linear dependence on the excitation power. In the linear response region of PS samples, addition of metal NPs layer moderately suppresses the emission while, in the saturation region, the net emission is enhanced by approximately up to 4-fold. Several possible mechanisms are discussed. We believe that the observed PL enhancement in saturation region is dominantly due to the resonant coupling between the LSP of Au NPs and the electronic excitation of PS, which inhibits the nonradiative Auger recombination process at high excitation power. These results indicate that the plasmon effect could be useful for designing even more efficient optoelectronic devices such as super bright light emitting devices and solar cells with high efficiencies. Despite many challenges, Au NPs can potentially be applied to introduce LSP resonance for the future silicon-based optoelectronics or photonics.
通过传统阳极氧化法制备了由具有局域表面等离子体（LSP）共振的金纳米颗粒（NPs）修饰的多孔硅（PS）样品。系统地研究了光致发光（PL），特别是其对激发功率的依赖性。发现未修饰的PS样品在PL强度上随着泵浦激光功率的增加呈现饱和行为，而金修饰的PS混合样品的发光对激发功率具有纯粹的线性依赖性。在PS样品的线性响应区域，添加金属NPs层适度抑制了发射，而在饱和区域，净发射增强了约4倍。讨论了几种可能的机制。我们认为，在饱和区域观察到的PL增强主要是由于金NPs的LSP与PS的电子激发之间的共振耦合，这抑制了高激发功率下的非辐射俄歇复合过程。这些结果表明，等离子体效应对于设计更高效的光电器件，如超亮发光器件和高效太阳能电池可能是有用的。尽管存在许多挑战，但金NPs有可能被应用于为未来的硅基光电子学或光子学引入LSP共振。
