Many Body Effects and Dynamics of High Density Excitons in Semiconductor Nano-Crystals

(1) AlGaAs/AIAs半导体量子线中激子的许多体效应和动力学研究了Al_xGa_<1-x>As/AlAs半导体量子线（QWR's）中激子光致发光（PL）的许多体效应及其动力学。阐明了量子阱中激子的积累动力学对许多体效应的动力学起重要作用。因此，高密度激子的相空间填充效应使PL在高密度激发下发生蓝移。另一方面，观察到激子沿量子阱的不对称扩散。在高密度激发下，激子扩散增强。(2)利用空间分辨简并四波混频技术研究了层状半导体纳米界面中激子的体效应和动力学，研究了BiI_3纳米界面上激子的孔隙动力学和空间动力学。进一步阐明了激子的量子态在保持量子相干的情况下进行宏观传播。激子量子态的空间传播动力学可以用包含激子间弱排斥相互作用的Gross-Pitaevskii方程来解释。(3)基体中半导体微晶中激子的许多体效应和动力学特性。在多孔聚合物和玻璃中生长出了Cul、HgI_2、PbI_2和TII微晶。研究了微晶中激子的体效应和激子-晶格相互作用。在Cul和HgI_2中，由于微晶化，出现了新的晶体结构和新的激子跃迁。在这些激子系统中，观察到了双激子的非线性发光和激子的非弹性散射。研究表明，晶体尺寸、温度和激发密度的改变会改变许多体效应的机理。另一方面，在TII、HgI_2和PbI_2微晶上，微晶与基体的相互作用增强了激子-晶格相互作用。在TII和HgI_2的情况下，从基体到微晶的有效能量转移决定了激子非线性发光的动力学。(4)功能化有机半导体纳米分子中激子的动力学研究了发光有机染料Alq3和六核6-甲基吡啶硫代铜(I)的光激发态动力学。在Alq3上，我们提出了一个新的光激发态模型，包括两个发光态和一个介导热活化的中间态。另一方面，揭示了光激发态的起源和动力学。少

(1) Many body effects and dynamics of excitons in AlGaAs/AIAs semiconductor quantum wiresMany body effects and their dynamics of excitonic photoluminescence (PL) in Al_xGa_<1-x>As/AlAs semiconductor quantum wires (QWR's) have been studied. It has been clarified that an accumulation dynamics of the excitons among the QWR's plays an important role on the dynamics of the many body effects. And as a result, a phase space filling effect of the high density excitons gives rise to the blue shift of the PL under high density excitation. On the other hand, an asymmetric diffusion of the excitons along the QWR's was observed. Under high density excitation, an enhancement of the exciton diffusion has been revealed.(2) Many body effects and dynamics of excitons in nano-interfaces of layered semiconductorsTemporal and spatial dynamics of the excitons localized at the nano-interface in BiI_3, have been investigated by a spatially resolved degenerated four wave mixing technique. As a result, It has b … More een clarified that the quantum state of the excitons propagate macroscopically in keeping the quantum coherency. The spatial propagation dynamics of the exciton quantum states can be explained by a Gross-Pitaevskii equation including a weak repulsive interaction among excitons.(3) Many body effects and dynamics of excitons in semiconductor microcrystallites in matricesMicrocrystallites of Cul, HgI_2,PbI_2 and TII embedded in the porus polymers and glasses have been grown. Many body effects and exciton-lattice interactions of the excitons in the microcrystallites have been studied. In Cul and HgI_2, novel crystal structures and novel exciton transitions appear as a result of micro-crystallization. On these exciton system, nonlinear luminescences of the bi-excitons and the inelastic scattering of the excitons were observed. It has been cleared that the mechanism of the many body effects changes by changing the crystal size, temperature and excitation density. On the other hand, on the microcrystallites of TII, HgI_2 and PbI_2, the exciton-lattice interactions are enhanced by the interaction between the microcrystallites and matrices. In the case of TII and HgI_2, the effective energy transfer from the matrices to the maicrocrystallites governs the dynamics of the nonlinear luminescence of the excitons.(4) Dynamics of excitons in functional organic semiconductor nano-moleculesDynamics of the photo-excited states providing the luminescence of the luminous organic dye Alq3 and the hexanuclear 6-Methylpyridinethiolato-Copper (I) have been studied. On the Alq3, we have proposed a new model for the photo-excited state including two-luminescent states and a intermediate state mediating thermal activation. On the other hand, the origin and dynamics of the photo excited states have been revealed. Less