School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
J Am Chem Soc. 2012 Oct 3;134(39):16155-8. doi: 10.1021/ja3075902. Epub 2012 Sep 24.
We observe and systematically tune an intense mid-infrared absorption mode that results from phosphorus doping in silicon nanowires synthesized via the vapor-liquid-solid technique. The angle- and shape-dependence of this spectral feature, as determined via in-situ transmission infrared spectroscopy, supports its assignment as a longitudinal localized surface plasmon resonance (LSPR). Modulation of resonant frequency (740-1620 cm(-1)) is accomplished by varying nanowire length (135-1160 nm). The observed frequency shift is consistent with Mie-Gans theory, which indicates electrically active dopant concentrations between 10(19) and 10(20) cm(-3). Our findings suggest new opportunities to confine light in this ubiquitous semiconductor and engineer the optical properties of nontraditional plasmonic materials.
我们观察并系统地调整了一个强的中红外吸收模式，该模式是通过汽-液-固技术合成的硅纳米线中的磷掺杂引起的。通过原位传输红外光谱确定的这种光谱特征的角度和形状依赖性支持将其分配为纵向局域表面等离子体共振（LSPR）。通过改变纳米线长度（135-1160nm）来实现共振频率（740-1620cm(-1)）的调制。观察到的频率位移与 Mie-Gans 理论一致，表明掺杂剂的电活性浓度在 10(19)到 10(20)cm(-3)之间。我们的发现为在这种无处不在的半导体中限制光和工程非传统等离子体材料的光学性质提供了新的机会。
