NON-TECHNICAL PROJECT ABSTRACT This 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.
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.
