CAREER: Synthesis and Electronic/Electrical Properties of Carbon Nanotube Junctions Wenzhi LiFlorida International UniversityDMR One of the objectives of this research is to study and understand fundamental synthesis mechanism of new functional materials: Y- shaped carbon nanotube junctions (Y-junctions). Figure a shows a scanning electron microscope (SEM) image of a Y-junction. It consists of many branches and forms a multiple junction. Figure b shows a transmission electron microscopy (TEM) image of a Y-junction. The outer and inner diameters of the Y-junction are 70 nm and 15 nm, respectively. Energy Dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD) are employed to determine the chemical composition of the catalyst, which is catalyzing the formation of the Y-junction nanotubes. EDX shows that the as- synthesized material consists of C, O, Co, Mg, and S. XRD further indicates that C, CoS, MgO, and MgS are presented in the sample. Initial analysis of the EDX and XRD data indicates that CoS nanoparticles are promoting the formation of the branched carbon nanotubes. a, A multi-branch Y-junction dispersed on silicon substrate. All the branches have same diameter of 70 nm. b, TEM image of the branched nanotube, showing the hollow core structure. c, EDX shows that the as-synthesized material consists of C, Co, Mg, O, and S. (note: Si is from silicon specimen holder and Au is from gold coating, which is used to reduce charging effect for SEM imaging.)

CAREER: Synthesis and Electronic/Electrical Properties of Carbon Nanotube Junctions Wenzhi LiFlorida International UniversityDMR Education and Outreach: Two graduate students (Bimal Pandey and Tao Zhang) are taking part in the proposed nanoscale material research. They are preparing their first scientific papers basing on their research findings. Two undergraduate students (David Puldon and Richard Galvez) did their independent study under the PI’s supervision and they were involved in the research on Y- junction nanotubes and carbon nanotube/ceramic composites. Four Miami-Dade high school students took summer research in the PI’s laboratory on nanomaterial synthesis and thin film deposition. Students have gained hands-on skills in chemical vapor deposition and electron beam deposition techniques, and have had chance to observe their own samples (carbon nanotubes) by using scanning electron microscope. Three of the four students will continue their research in the Fall semester in Collaborating with the FIU “Physics Learning Center” and the “Center for High Energy Physics Research & Education Outreach”, the PI has given lab tours and demonstrated his research results to about 150 K-12 students, parents, and teachers. This activity will generate strong student and public interest in and understanding of nanoscience and nanotechnology. The PI is demonstrating his ongoing nanoscience research to Miami-Dade high school teachers, who are joining the Physics Modeling Workshop at FIU in summer Miami-Dade High school students (from left to right: Charlie DeVivero, Ankur Shah, Charles de las Casas, and Jose Rocha) are setting up an electron beam evaporator for thin film deposition in summer 2006.