The objective of this program is to investigate a novel photoresponse behavior in single-wall carbon nanotube - silicon based heterojunction architectures. A combination of experimental and theoretical studies will be used to understand the origin of this phenomenon. Using these architectures, high-performance optoelectronic switches for proof-of-concept circuit elements such as phototransistors, logic gates, and analog-to-digital converters will be developed. The intellectual merit of the proposed work lies in unfolding the physics of the newly observed phenomenon, and overcoming the engineering challenges that will enable the development of high performance devices. The role of novel mechanisms such as the multiple exciton generation process, and the impact of band structure of carbon nanotubes-silicon heterojunctions on carrier injection will be investigated. Understanding the origin of this novel phenomenon and its application in advanced optoelectronic architectures comprise a transformative research thrust, which will combine expertise in experimental and theoretical aspects of the physics of nanoscale devices and pioneering techniques of nanoscale materials assembly and integration. The broader impacts of this program include compelling educational and research experiences for graduate, undergraduate and high-school students. A combination of exposure to state-of-the-art materials synthesis, characterization and device fabrication methods, a possibility of international research, and education in physics, chemistry, materials science and electronics of low-dimensional systems will appropriately prepare them for both academic and non-academic careers. Short-term "educational research" modules for undergraduates, co-ops, and high-school students; graduate curriculum development and educational modules for young scholars; and a focus on minority involvement are synergistically integrated into the program.
