This project will replace semiconductor wafers with crystalline semiconductor nanoparticles. This would allow the construction of three-dimensional circuits (more than one layer of transistors) and the integration of otherwise chemically and structurally incompatible single-crystal materials on a single substrate. Such substrates could include low loss ceramics or low cost, flexible plastics. High-density silane plasmas will be used for forming these nanoparticles. Electronic and optoelectronic systems are typically built from integrated circuits, lasers, and other devices that are individually packaged and assembled on a board. These devices are built on crystalline semiconductor wafers that are mutually incompatible. The hybrid assembly approach required therefore greatly limits overall system performance. The research group has already shown that nearly cubic, single crystal silicon particles can be synthesized with dimensions of 30 to 150 nm. Nanoparticles will be electrically charged and electrostatic forces will be used to assemble them at predetermined sites on a substrate. This will be accomplished using charge transfer from a flexible stamp. High performance transistors using these nanoparticles will be built and numerical models for them developed. Early results suggest that Schottky barrier field effect devices are most suitable for this application. High resolution electron microscopy will be used to support this work, in particular, the development of the critical metal-semiconductor contacts.
Since nanoparticle devices is a new field of study, it is expected that students graduating will become leaders in this field and will help disseminate the technology. Outreach will be an important part of the NIRT as it will integrate with existing MRSEC and IGERT outreach programs, particularly drawing in Native American students and faculty into this new research area. The group also anticipates supporting at least two US citizen female graduate students in the program as they are currently working in this area under IGERT and MRSEC sponsorship. In addition, the PIs will develop new web-based resources to educate the broader community about nanoparticle devices, including both charge storage devices and the nanoparticle/quantum dot structures.
