NER: Engineering of InAs Quantum Dot Ensembles Using Interference of Optical Surface Waves

NER：利用光学表面波干涉进行 InAs 量子点系综工程

• 批准号: 0210279
• 负责人: Serge Oktyabrsky
• 金额: $ 9.03万
• 依托单位: SUNY at Albany
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2003-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0210279&HistoricalAwards=false
• 关键词: NER; Engineering; InAs; Quantum; Dot

Engineering of InAs Quantum Dot Ensembles Using Interference of OpticalSurface WavesThis project addresses the problem of inhomogeneous broadening of the sizedistribution of quantum dot (QD) epitaxial semiconductor ensembles formedvia a stress-driven Volmer-Weber or Stranski-Krastanov growth mechanism. Theuniformity and narrow size distribution of the QDs are the major challengesfor the utilization of QD structures in optoelectronic devices. The primarygoal of this proposal is to evaluate the feasibility of nanoscale control ofthe nucleation process of InAs QDs on a GaAs surface using the interferenceof the optical surface waves. The interference pattern will be generated onthe surface of the substrate using a pulsed UV laser during the growth ofQDs by molecular beam epitaxy (MBE). The pattern, with a typical period offew hundred nm, will be created using two different optical schemes basedon: (i) the interference of the incident wave with the scattered coherentsurface wave; and (ii) the interference of the incident waves with twosurface waves coupled to the split laser beams. The optical interferencepattern will modulate periodically the surface properties of the substrateat 100-200 nm level. The nucleation of QDs will be controlled through eithersubstrate temperature modulation, thereby destroying the nucleation clustersin the antinode of the standing wave pattern, or through undulation of thesurface by laser ablation to control the surface energy. The 100-nmmodulation scale is expected to form a template for initial QD nucleation,and the subsequent evolution of the QD ensemble will be driventhermodynamically towards higher density of dots, (3-10)e10 cm-2. Theimportant features of the in-situ optical impact are that it does not leaveany residues on the surface, can be conducted during the growth process, andcan be adjusted to introduce the minimum defect density.We will systematically investigate the factors (growth temperature, As flux,growth rate, laser power, etc.) that provide uniform and narrow QDdistribution and efficient luminescence. The samples grown using opticallycontrolled nucleation will be studied by the in-situ RHEED, as well as STM,TEM and photoluminescence methods to reveal the correlations between growthparameters, and the structure and properties of the QD systems. Thelaboratories at the Institute have all the necessary equipment for the QDcharacterization. This includes state-of-the-art field-emission ultra-highresolution TEM, focused ion beam station, surface analysis tools, five STMtools configured for different imaging modes and environment includingultra-high vacuum, and unique ultrasonic force microscope.The successful completion of the proposed work would have a significantimpact on the performance of various optoelectronic components. The methodwill allow the growth of QD structures with sharp size distribution and highradiative recombination efficiency. For example, the QD structures will beused as active media for laser diodes with superior performancecharacteristics, such as higher efficiency, higher thermal stability, highermodulation frequency and increased reliability.

利用光学表面波的干涉设计InAs量子点系综这个项目解决了通过应力驱动的Volmer-Weber或STranski-Krastanov生长机制形成的量子点(QD)外延半导体系综的尺寸分布不均匀展宽的问题。量子点的均匀性和窄的尺寸分布是量子点结构在光电子器件中应用的主要挑战。该方案的主要目的是评估利用光学表面波的干涉对InAs量子点在GaAs体表面成核过程进行纳米级控制的可行性。在分子束外延(MBE)生长量子点的过程中，使用脉冲紫外光激光器在衬底表面产生干涉图案。该图案的典型周期为100 nm，将使用两种不同的光学方案来产生：(I)入射波与散射相干表面波的干涉；以及(Ii)入射波与耦合到分割激光光束的两个表面波的干涉。光学干涉图案将在100-200 nm水平上周期性地调制衬底的表面性质。量子点的成核可以通过衬底温度调制来控制，从而破坏驻波图案反节点中的成核团簇，或者通过激光烧蚀表面的起伏来控制表面能量。100 nm调制尺度有望形成初始量子点成核的模板，随后量子点系综的演化将在热力学上朝着更高的点密度(3-10)E10 cm-2方向发展。原位光学撞击的重要特点是不在表面留下任何残留物，在生长过程中可以进行，并且可以调整以引入最小的缺陷密度。我们将系统地研究各种因素(生长温度、As流量、生长速度、激光功率等)。其提供均匀且窄的QD分布和有效的发光。用原位RHEED、扫描隧道显微镜、透射电子显微镜和光致发光等方法研究了光学控制成核法生长的样品，揭示了生长参数与量子点体系的结构和性能之间的关系。该研究所的实验室拥有描述QD特性的所有必要设备。这包括最先进的场发射超高分辨率透射电子显微镜、聚焦离子束站、表面分析工具、五种针对不同成像模式和环境配置的扫描隧道工具，包括超高真空，以及独特的超声力显微镜。这种方法将使量子点结构的生长具有尖锐的尺寸分布和高的辐射复合效率。例如，量子点结构将被用作激光二极管的有源介质，具有更高的效率、更高的热稳定性、更高的调制频率和更高的可靠性等优异性能。