Fabrication and analyses of intermixing in InGaAs/InGaAsP and InGaAsP/InP quantum welld and their use in intermixed quantum-well lasers and integrated laser-modulator structures

量子阱混合依赖于在热退火处理过程中扩散通过量子阱和相邻势垒层的点缺陷的非平衡浓度的产生，导致量子阱尺寸和组成的变化。目前，很少有直接研究量子阱结构内部由于混合引起的物质重分布的研究。为了制备具有空间波长特征的InP和gaas基量子阱结构，提出了利用分析电子显微镜测定量子阱混合引起的组成和形态变化。观察组成剖面中温度相关变化的能力将允许直接测量由于量子阱混合而导致的元素扩散，并确定该过程的活化能。从退火样品的浓度分布曲线中获得的有效扩散系数将有助于更好地理解每个特定体系的特定扩散机制（即本征点缺陷平衡和非平衡条件下的取代-间隙和空位机制）。结果将与基于光致发光波长位移的理论计算进行比较，因此，将大大提高我们对半导体材料中发生的扩散和相互扩散机制的认识。这项工作的目的是定制材料的光学特性，以生产用于医疗诊断和集成光电子等一系列光电子应用的光电子器件。特别地，我们将首先关注脊型集成激光调制器模块的制造和加工，它在广泛的高速光信号处理设备中具有潜在的应用。随后，我们将扩展这些研究，包括集成分布式反馈激光调制器模块。此外，我们将继续研究光电器件的可重复性和长期可靠性，并应用这些知识来评估我们制造的器件。

Quantum-well intermixing relies on the creation of non-equilibrium concentrations of point defects that diffuse through the quantum wells and adjacent barrier layers during thermal-anneal treatment, causing changes in the quantum-well dimensions and composition. At present there are few direct compositional studies that look into redistribution of material inside quantum- well structures due to intermixing. It is proposed to use analytical electron microscopy to determine the compositional and morphological changes induced by quantum well intermixing in order to fabricate InP and GaAs-based quantum-well structures with spatial wavelength characteristics. The ability to observe temperature-dependent changes in the compositional profiles will permit the direct measurement of the diffusion of elements due to quantum-well intermixing and to determine the activation energies of the process. The effective diffusion coefficients obtained from the concentration profiles of annealed samples will lead to better understanding of the particular diffusion mechanism for each particular system (i.e. the substitutional-interstitial and the vacancy mechanisms under intrinsic point defect equilibrium and non-equilibrium conditions). Results will be compared with theoretical calculations based on photoluminescent- wavelength shift and, therefore, will significantly improve our knowledge of the diffusion and interdiffusion mechanisms that take place in semiconductor materials.The objective of this work is to tailor the optical properties of the materials in order to produce optoelectronic devices for use in a range of optoelectronic applications such as medical diagnostics and integrated optoelectronics. In particular, we will be initially concerned with the fabrication and processing of ridge-type integrated laser-modulator modules, which have potential applications in a wide range of high-speed optical-signal processing equipment. Later we will extend these studies to include integrated distributed feedback laser-modulator modules  Also, we will continue our studies on the reproducibility and long-term reliability of optoelectronic devices, and apply the knowledge to evaluate our fabricated devices.