硅基激光器是实现新一代与硅集成电路兼容的光通信和光互连芯片级光电子集成核心器件。但目前直接外延硅基激光器的光电性能距离实用化还有很大的差距，这主要归因于直接外延GaAs/Si材料的高位错密度和热应力。本项目提出一种采用硅基纳米尺寸图形衬底侧向外延结合金属有机化学气相沉积方案，探索应用硅图形衬底侧向外延高质量GaAs/Si材料生长方法，并制备InAs/GaAs量子点激光器材料和器件。重点优化图形衬底结构和侧向外延生长条件，利用大高宽比图形掩膜结构阻挡穿透位错机制，有效降低硅基激光器有源区的位错密度和材料热应力。同时，采用低温GaInP上限制层和p型调制掺杂方法，优化分别限制结构和量子点有源区及其生长条件，避免量子点光电性能退化，增加光学模式增益。此方案具有同时减小材料位错密度和热应力的优点。拟通过本项目实施，实现波长1.3微米硅基量子点激光器的低阈值高可靠性室温工作，为器件实用化奠定基础。

Si-based lasers are core devices for realization of new generation optoelectronic integration, which is chip-scale optical communication and interconnection for compatibility with Si integrated circuit. Unfortunately, their performance is still poor for practical application due to the high-density dislocations and thermal stress in GaAs/Si epilayers. In this project, the strategy for epitaxial lateral overgrowth of GaAs layers on nano-scale Si-based patterned substrates using metal-organic chemical vapor deposition has been proposed to fabricate high-quality GaAs/Si epilayers and InAs/GaAs quantum dot laser materials and devices. Optimizing the patterned structure and growth conditions of the epitaxial lateral overgrowth, the dislocation density and thermal stress can be reduced efficiently by using the patterned structure with large aspect ratio. Meanwhile, the growth conditions and separate-confinement structure will be optimized to supply proper optical and carrier confinement, and the low growth-temperatrue GaInP upper cladding layer and the modulation p-doping will be used to avoid the degradation of the optical properties of quantum dots, and increase optical modal gain. The strategy has the advantage of simultaneous reduction both the dislocation density and thermal stress. Through implementation of the project, optimum material structure and growth condition will be explored to reduce the dislocation density and obtain the quantum dot with high optical gain. Therefore, the 1.3 um wavelength Si-based InAs/GaAs quantum dot laser with low threshold current and high reliability at room-temperature will be achieved. This project is significant for both basic research and practical applications of Si-based InAs/GaAs quantum dot lasers.