| Exploiting materials of dimensions less than 100 nm for potential applications has been proven a fascinating enterprise. However, efforts so far have concentrated on individual nanostructures. The collective behaviors of nanostructures in a large ensemble remain largely unexplored. As the first step into the nano realm, investigation of isolated nanostructures and characterization of individual nanodevices are of great importance and naturally of strong appeal to researchers. Yet more challenging and probably of greater impact is the assembly and manipulation of multiple nanostructures into integrable functional units. It is both desirable and timely to seek ways to advance both fabrication capabilities and scientific explorations beyond the realm of individual nanostructures.; In this work, a non-lithographic technique that utilizes highly ordered anodized aluminum oxide (AAO) porous membrane as a template is developed as a general fabrication means for the formation of arrays of vastly different 2-dimensional (2D) lateral superlattices. The fact that material systems as different as metals, semiconductors, and carbon nanotubes can be treated with the same ease attest to the generality of this nanofabrication approach. The original AAO membranes determine the uniformity, packing density, and size of the nanostructures. Flexibility of using a variety of materials, accurate control over fabrication process, and command over AAO template attributes give us the freedom to engineer various physical properties determined by the shape, size, composition, and doping of the nanostructures. The novel nanomaterial platform realized by this unique technique enables a broad range of applications.; A fundamentally new nanoheteroepitaxial growth method based on the as-fabricated semiconductor nanostructures was explored. Employing this approach, high quality semiconductor thin films and quantum dots have been successfully grown by molecular beam epitaxy on nanopatterned semiconductor substrates. Optical and structural characterizations confirmed the improved material properties. These techniques lead the way to controlled growth of periodic quantum dot superstructures and to significant improvement of III-nitride heteroepitaxy for device applications. |
