Investigation of fundamental physical properties of coupled quantum well - quantum dot systems emitting in the near infrared range of 1.3 - 1.55 micrometer (Acronym: QuCoS = Quantum Coupled Systems).

本研究的主题是研究耦合二维（量子阱）和零维（量子点）半导体量子子系统的基本物理性质，其基态光子发射波长在近红外（1.3-1.55 um）光谱范围内。>>>>该项目的主要目标是对几个密切相关的问题进行理论和实验研究，以获得以下方面的知识：---- (i)重要的物理相互作用，它可以解释空间分离但仍然是量子力学耦合的量子阱（QW）和量子点（QD）子系统（例如电子/空穴-光学/声学声子，激子-激子或载流子-载流子相互作用过程）之间的非共振电荷/激子/自旋转移；---- (ii) qw耦合- qd系统中的载流子/激子/自旋弛豫路径，主要取决于弛豫介导的散射过程的耦合强度和效率；---- (iii)系统中材料成分/应变对俄歇过程效率和量子阱与点之间俄歇辅助载流子转移的影响；---- (iv)考虑到温度、载流子/激子居群、半导体材料的化学含量及其电子结构等因素，控制QW和QD之间量子力学耦合强度的可能性；---- (v) qw耦合- qd系统中电荷/激子/自旋转移后光注入/自旋初始化过程的相干和非相干动力学性质及其控制；---- (vi)耦合QW和QD系统的自旋相关性质。>>>>我们打算验证的假设是，通过仔细选择物理相互作用和半导体材料特性，可以设计和生产一个量子系统，该系统具有广泛和精确可控的电荷/激子/自旋从QW转移到QD基态的效率，两者在实际空间中分离，同时保持三个条件：(1)量子点基态是整个耦合系统的最低能态，(2)它保持局域化特征（类原子特征），(3)在1.3-1.55 um的近红外光谱范围内发射光子。>>>>作为一个长期目标，我们预计我们的调查结果将指出与期望参数的耦合QW-QD系统设计相关的最关键问题。我们打算验证不同维度的空间分离子系统之间的量子力学耦合的作用，并演示如何在基本物理层面上控制它。这些知识将可能用于开发新型光电和自旋电子器件，这些器件具有优越的参数（即快速调制激光器，开关，长存储时间和快速读写存储器等），这些器件依赖于qw耦合- qd系统架构。

The subject of this research is to investigate the basic physical properties of coupled two-dimensional (quantum well) and zero-dimensional (quantum dots) semiconductor-based quantum subsystems characterized by the ground state photon emission wavelength in the near-infrared (1.3-1.55 um) spectral range. >>>> The major aim of the project is to perform the theoretical and experimental studies of several closely related issues in order to acquire the knowledge on: ---- (i) important physical interactions, which can account for a non-resonant charge/exciton/spin transfer between spatially separated but still quantum-mechanically coupled quantum well (QW) and quantum dot (QD) subsystems (e.g. electron/hole-optical/acoustic phonon, exciton-exciton or carrier-carrier interaction processes); ---- (ii) carrier/exciton/spin relaxation pathways in the QW-coupled-QD system which should primarily depend on the coupling strength and efficiency of relaxation-mediated scattering processes; ---- (iii) the influence of material composition/strain in the system on the efficiency of Auger process and Auger-assisted carrier transfer between the quantum well and the dots; ---- (iv) possibilities to control the strength of the quantum-mechanical coupling between QW and QD, taking into account such factors as e.g.: temperature, carrier/exciton population, chemical content of semiconductor materials and their electronic structure; ---- (v) coherent and incoherent dynamic properties of charge/exciton/spin transfer followed by optical injection/spin initialization process and its control in the QW-coupled-QD system; ---- (vi) spin-related properties of a coupled QW and QD system. >>>> The hypothesis we intend to verify is that by a careful selection of physical interactions and semiconductor material properties one can design and produce a quantum system with widely and precisely controllable efficiency of charge/exciton/spin transfer from a QW to the QD ground state, both separated in the real space, while keeping three conditions: (i) the QD ground state is the lowest energy state for an entire coupled system, (ii) it keeps its localized character (atomic-like character), and (iii) emits photons in the near-infrared spectral range of 1.3-1.55 um. >>>> As a long-term objective, we anticipate that the results of our investigation will point out the most critical issues related to a design of the coupled QW-QD systems of desired parameters. We intend to verify the role of a quantum mechanical coupling between spatially separated subsystems of different dimensionality and demonstrate how to control it on the basic physical level. This knowledge will possibly be used in the development of novel optoelectronic and spintronic devices of superior parameters (i.e. fast modulated lasers, switches, long storage time and fast read/write memories etc.), which rely on the QW-coupled-QD system architecture.