Department of Physics, University of Cincinnati , Cincinnati, Ohio 45221-0011, United States.
Nano Lett. 2011 Oct 12;11(10):4329-36. doi: 10.1021/nl202433g. Epub 2011 Sep 16.
The internal electronic structures of single semiconductor nanowires can be resolved using photomodulated Rayleigh scattering spectroscopy. The Rayleigh scattering from semiconductor nanowires is strongly polarization sensitive which allows a nearly background-free method for detecting only the light that is scattered from a single nanowire. While the Rayleigh scattering efficiency from a semiconductor nanowire depends on the dielectric contrast, it is relatively featureless as a function of energy. However, if the nanowire is photomodulated using a second pump laser beam, the internal electronic structure can be resolved with extremely high signal-to-noise and spectral resolution. The photomodulated Rayleigh scattering spectra can be understood theoretically as a first derivative of the scattering efficiency that results from a modulation of the band gap and depends sensitively on the nanowire diameter. Fits to spectral lineshapes provide both the band structure and the diameter of individual GaAs and InP nanowires under investigation.
利用光调制瑞利散射光谱可以解析单根半导体纳米线的内部电子结构。半导体纳米线的瑞利散射对偏振非常敏感，这使得仅从单根纳米线散射的光可以采用几乎无背景的方法进行检测。虽然半导体纳米线的瑞利散射效率取决于介电对比度，但它作为能量的函数相对没有特征。然而，如果使用第二束泵浦激光对纳米线进行光调制，则可以以极高的信噪比和光谱分辨率解析内部电子结构。光调制瑞利散射光谱可以从理论上理解为散射效率的一阶导数，该散射效率源于带隙的调制，并且对纳米线直径非常敏感。对谱线形状的拟合不仅提供了正在研究的 GaAs 和 InP 纳米线的能带结构，还提供了它们的直径。
