Nanostructured solid-state materials: from fundamental properties to optoelectronic technologies

固态材料，特别是半导体中的电荷传输是许多现代技术的基础，从晶体管到发光体和太阳能电池。在纳米尺度上对这些材料的结构进行修改和/或组织是减小器件尺寸和不断开发利用新现象（包括量子限制效应）的创新器件的自然研究途径。在这些纳米结构和纳米结构材料中，基元激发和电荷输运机制被发现是根本不同的。在宏观尺度上，纳米结构的组装和复合纳米材料的工程也可以产生新的特性。太赫兹（THz）辐射是研究这些材料中电子输运性质的一个非常有力的探针。过去十年的技术进步帮助开发了高性能的太赫兹光谱系统。特别是，现在可以使用宽带源和探测器（0.1至超过10 THz，或0.4至超过40 meV）和低噪声THz光谱系统，用于研究极高频率下的传输机制。时域太赫兹光谱技术可以应用于从金属到半导体和绝缘体的各种固态材料。动力学现象和非平衡性质也可以通过使用额外的光脉冲束和时间分辨测量飞秒到纳秒的时间尺度进行研究。这些最先进的太赫兹技术使纳米技术、材料科学、电子学和光电子学领域的基础和应用研究成为可能。

Transport of charges in solid-state materials, in particular semiconductors, is the basis of many modern-day technologies ranging from the transistor, to light emitter, and solar cells. Modifications and / or organization of the structure of these materials at the nanoscale are natural research avenues to reduce the size of devices and to continually develop innovative devices that take advantage of new phenomena, including quantum confinement effects. The elementary excitations and charge transport mechanisms are found to be fundamentally different in these nanostructures and nanostructured materials. New properties can also emerge from the assembly of nanostructures and the engineering of composite nanomaterials on a macroscopic scale. The terahertz (THz) radiation is an extremely powerful probe to study electronic transport properties in these materials. Technological advances of the last decade have helped develop performant terahertz spectroscopy systems. In particular, it is now possible to work with broadband sources and detectors (0.1 to more than 10 THz, or 0.4 to more than 40 meV) and low-noise THz spectroscopy systems, for the study of transport mechanisms at extremely high frequencies. Time-domain THz spectroscopy techniques can be applied to a large variety of solid-state materials from metals, to semiconductors and insulators. Dynamical phenomena and non-equilibrium properties can also be studied through the use of an additional optical pulsed beam and time-resolved measurements on femtosecond to nanosecond time scales. These state-of-the-art terahertz techniques enable fundamental and applied studies of great interest in the fields of nanotechnologies, materials sciences, electronics and optoelectronics.