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在适当的成像条件下可以直接从高分辨透射电子像(HRTEM)以接近原子级的分辨率进行晶格畸变分析。本综述介绍晶格畸变分析(LADIA)程序包及其在半导体自组装量子点(QD)系统中的应用。对多层InP小QD系统中畸变分布的分析表明:光致发光(PL)能量峰位的红移和QD中的应变弛豫直接相关。在慢速生长的InAs大QD系统中应变引起的元素互溶是PL峰位蓝移的主要因素。多层系统中QD的垂直叠合可解释为间隔层厚度低于临界值时生长前沿的横向张应变的作用。研究了生长以后不同条件快速退火对QD稳定性的影响,观测到垂直叠合的InP QD中出现各向异性的退火不稳定性。
Under proper imaging conditions, lattice distortion analysis can be performed directly from high resolution transmission electron microscopy (HRTEM) with near-atomic resolution. This review presents the Lattice Distortion Analysis (LADIA) package and its application in semiconducting self-assembled quantum dots (QD) systems. The analysis of the distortion distribution in a multilayer InP small QD system shows that the redshift of the PL peak energy is directly related to the strain relaxation in the QD. Strain-induced elemental miscibility in slow-growing InAs large QD systems is a major contributor to blue-shift of the PL peak. The vertical stacking of QDs in a multilayer system can be explained by the effect of the transverse tensile strain at the growth front when the thickness of the spacer layer is below the critical value. The effects of rapid annealing under different conditions on the stability of QD were studied. Anisotropic annealing instability was observed in vertically-stacked InP QDs.