一维半导体纳米线体系的光谱和光学性质研究

【作者】 黄少华；

【导师】 沈学础； 陈张海；

【作者基本信息】 复旦大学 ， 光学， 2006， 博士

【摘要】 半导体低维结构(如量子阱、超品格、量子线和量子点等)的物性研究、样品生长及器件制作，已成为当前凝聚态物理研究的前沿热门课题之一。其中，半导体一维量子线结构因其具有丰富有趣的物理内涵和光电功能器件应用的前景而倍受关注。本文主要利用多维分辨的光谱实验手段(空间、时间、自旋分辨)，结合两种具有不同特点的代表性样品分别研究了Ⅲ-Ⅴ族和Ⅱ-Ⅵ族这两类处于不同光谱波段的直接带隙准一维纳米线体系的光电特性。具体包括以下几方面： 1．利用显微光致发光光谱研究经选择性离子注入和快速热退火后的单根GaAs／AlGaAs量子线结构体系中的载流子在输运、复合发光等方面的一维特性。同时，对低温下准一维激子局域化的行为进行讨论。此外，通过对量子线的磁阻测量，揭示一维结构中载流子在磁场中的输运行为。 2．首次根据四角晶须状ZnO纳米结构的天然的空间几何构型，采用不同的Raman散射配置，研究单个纳米结构的具有高空间分辨率的偏振Raman二维扫描谱。借助溫度变化调制一维ZnO纳米棒中的能级结构，研究了共振Raman散射谱线重分布行为，以及多声子散射从入射共振到出射共振的转变过程。此外，细致讨论了LO声子频移的主要物理根源。 3．研究一维ZnO纳米棒体系中，具有不同跃迁选择定则的双光子吸收和单光子吸收诱导光致发光光谱，揭示一维ZnO纳米体系中的能带结构。根据双光子吸收诱导光致发光光谱强烈依赖激发功率的非线性特点，讨论了非线性吸收的三个主要阶段，以及与双光子非线性特性相关的激子-激子多体相互作用导致的能带填充效应。并且，经由双光子诱导光致发光激发谱，我们细致研究了双光子近共振效应，进而对一维ZnO纳米棒的能带结构有更深入的了解。 4．针对近年来快速发展起来的激光共焦扫描显微光谱技术，结合不同生长方法制备的具有不同样品特点的低维结构，从显微光致发光和显微拉曼散射空间扫描谱两方面，探讨单个纳米结构体系的光谱表征。更多还原

【Abstract】 Low dimensional semiconductor system, such as quantum well (QW), superlattice (SL), quantum wire (QWR) and quantum dot (QD), et al., were investigated extensively lately, involving the fundamental physical properties, materials fabrication and devices development. The interest in one-dimensional (ID) QWRs is fueled and fanned by its potential abundant physical phenomena and prospects in optoelectronics application. In this dissertation, the optical and electronic properties in typical direct band-gap III-VandII-A/I quasi-1D system within the different spectral region were studied. The details are as follows:1. Quasi-1D features in carrier transport, recombination and emission, et al., were studied in the V-grooved QWR samples modified by selective ion-implantation and rapidly thermal annealing, by means of Micro-photoluminescence (PL) and magneto-transport measurement. The localized 1D exciton behavior was observed in low temperature.2. The x-y spatially-resolved mapping of polarized Raman scattering spectra from a single tetrapod-like ZnO nanostructure were proposed and performed, with different polarized scattering configuration by utilizing the intrinsic geometry configuration. The resonant Raman scattering spectra were redistributed by tuning the energy band modulated by the temperature; a transformation behavior from incoming to outgoing resonant Raman scattering process was also observed. In addition, detail discussions were provided to explain the LO phonon Raman shift with increasing the temperature.3. To deeply reveal the energy band structure in well-aligned 1D ZnO nanorods, both one-photon- and two-photon-induced PL, with different transition selection rules, were performed in detail. Due to two-photon absorption strongly relies on the excitation power, three nonlinear optical absorption processes in different power density regime and band filling effect related to the many-body interaction among excitons,were traced in detail. Furthermore, a two-photon-induced PL resonant effect was confirmed by tuning the excitation wavelength from below the middle of the band-gap to above it, therefore we could get further insight of the band structures in ZnO nanorods.4. The confocal mapping Micro-spectral techniques, in conjunction with distinct low-dimensional structure and/or spectral features of the samples produced by different fabrication methods, were performed to characterize the single nanostructure.更多还原