IMR: Development of Instrument: Improving Homogeneity of Quantum Dot Size, Shape, Positioning for Student Training

这项建议是为了开发一种新的仪器，它将允许以更高的精度和质量制造纳米级粒子。该仪器的设计是在特定位置沉积均匀的纳米晶体，并克服当前技术所面临的障碍，即在10%至20%的位置错位300或400 nm时生产尺寸均匀度较差的纳米颗粒。这些数字严重限制了使用纳米材料进行创新的机会。相比之下，拟议的仪器是基于一种新的生长方法，该方法使用独特设计的纳米喷嘴沉积纳米结构，显示出将电流均匀性和定位精度提高10倍的潜力，从而开创了纳米材料及其应用的新纪元。它创造了制造和探索新材料的机会，通过将纳米粒子分组在一起，形成高度有序的链、分子或固体类似晶格结构的阵列。例如，使用这种仪器，人们可以构建新型的光学和化学传感器阵列；用于更小、更功能的电子设备的纳米级电路；或者正好安装在处理器芯片上的存储器阵列，从而显著提高计算设备的速度。具有新颖性能的创新材料结构可以带来新的和更好的设备的机会是巨大的。这项提议还将给研究生和本科生提供机会，领导现有新仪器的设计和制造，以及独特纳米结构的生长和表征。这些学生将探索一种新的途径来实现更均匀的有序纳米结构阵列，并认识到它们在具体应用中的影响。技术项目摘要尽管纳米技术带来的可能性非常令人兴奋，但由于一直伴随着量子点生长的成核的大小、形状和随机位置的相当大的不均匀，这些可能性尚未完全实现。虽然克服这一障碍的努力已经发现了重要的基础科学以及实现改善均匀性的技术，但均匀性仍然保持在10%到20%左右，定位仅限于量子点大小的数量级。这项提议是在一种相对较新的生长方法--定向液滴外延的基础上开发一种新的仪器，有可能在这些数字上有显著改善。这项提议将建造和探索一种新的工具，在特定位置沉积受控体积的液滴。这项技术基于一个简单的想法，即在结晶之前，通过中空扫描探头尖端的纳米孔将液滴直接转移到衬底上。这种技术可以减少尺寸的不均匀性以及至少一个数量级的随机定位。它为探索两个不同距离的量子点的光学行为提供了可能。合作排放在时间、大小和分布上都将是令人惊叹的研究。随着量子点的数量慢慢增加，以探索预期的超辐射发射，事情甚至变得更加令人兴奋。这使得研究不同的量子点几何排列甚至组成成为可能。它创造了探索2D或3D QD阵列或缺少QD的QD阵列的机会。此外，人们还可以探索量子线(QWR)，在光学腔中精确排列的量子点，或者新一代电路？由QWR连接的量子点组成。这项提议还将使研究生和本科生有机会领导现有仪器的设计和制造，以及独特纳米结构的生长和表征。这些学生将探索一条实现更均匀的有序纳米结构阵列的新途径，并认识到它们对具体应用的影响。

NON-TECHNICAL PROJECT ABSTRACTThis proposal is to develop a new instrument that will allow the fabrication of nanoscale particles with much higher precision and quality. The instrument is designed to deposit uniform nanoscale crystals at specific locations and overcome a roadblock faced by current techniques which produce nanoscale particles with poor size uniformity at 10 to 20% with positioning misalignment of 300 or 400nm. These numbers severely limit the opportunities for innovation using nanoscale materials. In contrast, the proposed instrument is based on a new growth approach which uses a uniquely designed nanoscale nozzle to literally deposit nanostructures with a demonstrated potential for 10 times improvement on current uniformity and precision of location, enabling a new era of nanomaterials and their application. It creates the opportunity to fabricate and explore new materials by grouping nanoscale particles together to form highly organized arrays in chain, molecule, or solid like lattice structures. For example, using this instrument one can construct novel optical and chemical sensor arrays; nanoscale circuits for smaller and more functional electronic devices; or memory arrays that fit right on a processor chip, dramatically increasing the speed of computation devices. The opportunity for innovative material structures with novel properties that can lead to new and better devices is enormous.This proposal will also give graduate and undergraduate students the opportunity to lead the design and fabrication of an exiting new instrument as well as the growth and characterization of unique nanostructures. These students will explore a new path to achieve a more homogeneous array of organized nanostructures and recognize their impact with specific applications.TECHNICAL PROJECT ABSTRACT Although the possibilities from nanotechnology are very exciting they have yet to be fully realized due to the rather large inhomogeneity in the size and shape and random position of nucleation that have persistently accompanied the growth of quantum dots. While efforts to overcome this roadblock have uncovered important basic science as well as techniques to achieve improved homogeneity, nevertheless uniformity remains around 10 to 20% and positioning is limited to the order of the quantum dot size. This proposal is to develop a new instrument based on a relatively new growth approach, ?directed droplet epitaxy?, with the potential for significant improvement on these numbers. This proposal will construct and explore a new instrument to deposit a controlled volume of liquid droplets at specific locations. The technique is based on the simple idea of transferring liquid droplets, through a nanoscale hole in a hollow scanning probe tip, directly onto a substrate before crystallizing. This technique can reduce the inhomogeneity in size as well as random positioning by at least an order-of-magnitude. It opens the possibility of exploring the optical behavior of two QDs with varying distance between them. The cooperative emission, in time, magnitude, and distribution, will be amazing to study. Things even get more exciting as the number of QDs is slowly increased to explore the superradiant emission expected. It makes possible investigating different QD geometrical arrangements or even compositions. It creates the opportunity to explore 2D or 3D QD arrays, or QD arrays with a missing QD. In addition, one can explore quantum wires (QWR), QDs placed in a precise arrangement in an optical cavity, or a new generation of an ?electrical circuit? composed of QDs connected by QWRs. The opportunity for innovative material structures with novel properties is enormous.This proposal will also give graduate and undergraduate students the opportunity to lead the design and fabrication of an exiting instrument as well as the growth and characterization of unique nanostructures. These students will explore a new path to achieve a more homogeneous array of organized nanostructures and recognize their impact with specific applications.