High-quality chalcogenide/oxide and manganese-doped semi-

1. IMAGES: self-assembled In2O3 mono- layer pattern (TEM, top-left), self-assembled cubic PbTe monolayer pattern (TEM, top-right), in-situ self-assembled Mn-PbSe nanoarrays (SEM, bottom-left) and single-crystal, defect-free and perfect hexa-gonal Bi2Te3 nanoplatelets (TEM, bottom-right). Synthesis, Characterization and Evolution Mechanism Study of Semiconductor Nanocrystals Jiye Fang, University of New Orleans,DMR-0449580 High-quality chalcogenide/oxide and manganese-doped semi- conductor nanocrystals (NCs) are inspired by thermoelectric and spintronic applications. Recently, we successfully synthesized mono- disperse NCs of PbSe, PbTe, Bi2Te3 and In2O3 with shape- and size- control by employing a high-temperature organic solution approach, demonstrating the feasibility of this synthetic strategy. (1) Investi- gations of In2O3 NCs (JACS, 127, 5276, 2005, top-left) imply that each NC is a single crystal with high-crystallinity, and the size of NCs is tunable. (2) A mechanism study of PbTe nanocrystalline evolution (JACS, 126, 11798, 2004, top-right) indicates that the shape of PbTe NCs can be developed from spherical to cubic structure when certain experimental parameters are well controlled. (3) A novel method for the large-scale, shape-controlled synthesis of 1D corrugated Mn- doped PbSe nanoarrays without using any capping polymer or ionic surfactant was developed (JACS, 126, 14816, 2004, bottom-left). (4) A uniquesynthesis of discrete, single-crystal, defect-free and hexa- gonal Bi2Te3 nanoplatelets was achieved, and a two-step epitaxial growth of the cylindrical strings of Bi2Te3 nanoplatelets on the Te rod surface by packing them along c-axis in a top-bottom-top- bottom sequence was proposed as well (JACS, 127, 10112, 2005, bottom-right). (5) To extend this synthesis approach to III-V semiconductor system, we are progressively synthesizing Mn- doped InP and GaP NCs with size- and shape-control.

2. Education and Outreach Team in Fang’s Nanofabrication Lab Four outreach interns from local high school were accepted in this group, and spent 6 weeks at University of New Orleans for learning synthesis and characterization of nanocrystals (top row, from left to right: high school teacher Ms. Kiko Sunderland and high school students Mr. Bryan Brothers, Mr. Philip Brunetti, Mr. Chris Hall) (www.ridgewoodprep.com/Chris%20Hall.htm). REU student (Miss Shanatrice Allen, 2nd row, the most right) from Dillard University also joined this group in the summer of 2005 and carried out a synthesis of low dimensional diluted magnetic semiconductor materials. She was selected as one of the three candidates who will receive a travel ward from AMRI to attend the AIChe 2006 Spring National Meeting/ World Congress on Particle Technology in April 2006. Several international exchange students were trained in this team as well (2nd row, from left: Miss Eun Young Shin from Korea, Miss Mario Andre from France and Mr. Narayan Sharma from India). The bottom row shows the core members of this team under current NSF project (from left): Dr. Jiye Fang (PI), Dr. Weigang Lu (PDF), Dr. Qingsheng Liu (PDF), and graduate students Mr. Zhaoyong Sun, Mr. Yizhong Wang, Mr. Jun Zhang, Mr. Yi Wang (not shown). Synthesis, Characterization and Evolution Mechanism Study of Semiconductor Nanocrystals Jiye Fang, University of New Orleans,DMR-0449580