Bulletin of the American Physical Society
74th Annual Meeting of the Southeastern Section
Volume 52, Number 13
Thursday–Saturday, November 8–10, 2007; Nashville, Tennessee
Session DA: Nanomaterial Physics and Applications |
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Chair: Richard Mu, Fisk University Room: Scarritt-Bennett Center Laskey Great Hall |
Thursday, November 8, 2007 1:30PM - 2:00PM |
DA.00001: White Light Emission from Ultrasmall CdSe Nanocrystals Invited Speaker: Magic-sized cadmium selenide (CdSe) nanocrystals have been pyrolytically synthesized. These ultra-small nanocrystals exhibit broadband emission (420 -710 nm) that covers most of the visible spectrum while not suffering from self absorption. This behavior is a direct result of the extremely narrow size distribution and unusually large Stokes shift (40-50 nm). The intrinsic properties of these ultra-small nanocrystals may lead to applications in solid state lighting and also provide the perfect platform to study the molecule-to-nanocrystal transition. [Preview Abstract] |
Thursday, November 8, 2007 2:00PM - 2:30PM |
DA.00002: Doping in ZnO Thin Films and Heterostructures Invited Speaker: As a direct bandgap material with emission in the ultraviolet, ZnO is of significant interest for ultraviolet light emitting diodes and laser diodes. The critical issues in developing such optoelectronic devices include p-type doping, minority carrier injection, and heterostructure formation. In this talk, the doping and transport of ZnO films and heterostructures will be reviewed and discussed. Of particular interest is the current understanding of minority carrier injection and electroluminescence behavior in heterojunction structures. [Preview Abstract] |
Thursday, November 8, 2007 2:30PM - 3:00PM |
DA.00003: Fabrication of Hetero-Structured Three-Dimensional Nanorod Arrays by Dynamic Shadowing Growth Invited Speaker: Multilayered heterogeneous one-dimensional (1D) nanostructures are important building blocks for nanodevice applications. A practical nanofabrication technique to produce heterogeneous nanostructures with arbitrary materials must meet the following criteria: (1) The ability to fabricate heterogeneous nanostructures with arbitrarily selected materials; (2) The ability to control the dimensions and uniformity of the heterogeneous nanostructures; (3) The ability to control the alignment of the heterogeneous nanostructures; (4) The ability to control the interfacial properties of the heterogeneous nanostructures. Here, we demonstrate a simple but versatile method to fabricate three-dimensional heterogeneous nanorod structures by multilayer dynamic shadowing growth (DSG). DSG is based on geometric shadowing effect and substrate rotation in a physical vapor deposition system. By programming the azimuthal rotation of the substrate, different shapes of aligned nanorod arrays, such as zig-zag, c-shape, spirals, etc, can be fabricated. With the change of the source materials during the deposition, we demonstrate that complicated heterostructured nanorod arrays, such as Si/Ni multilayer nanosprings, can be easily produced, and they exhibit particular magnetic anisotropic behavior. We also use DSG technique to design catalytic nanomotors with different geometries that are capable of performing different and desired motions in a fuel solution. Using the shadowing effect, a thin catalyst layer can be coated asymmetrically on the side of a nanorod backbone. Catalytic nanomotors such as rotary Si/Pt nanorods, rotary $L$-shaped Si/Pt and Si/Ag nanorods, and rolling Si/Ag nanosprings, have been fabricated, and their autonomous motions have been demonstrated in a diluted hydrogen peroxide solution. We observed that the catalytic decomposition of hydrogen peroxide on the surface of catalyst generated a propelling force to push the nanorod from the catalyst side. This fabrication method reveals an optimistic step towards designing integrated nanomachines. \newline \newline In collaboration with Yuping He and Junxue Fu, University of Georgia. [Preview Abstract] |
Thursday, November 8, 2007 3:00PM - 3:30PM |
DA.00004: An Ultrasensitive Resistive-Pulse-Sensing Scheme for Fluidic Devices Invited Speaker: We report on a resistive-pulse-sensing scheme to detect translocation of small particles through fluidic channels, which integrates the fluidic circuit and a metal-oxide-semiconductor field effect transistor (FET) and uses the FET's drain current modulation as an indication of the presence of particles inside the fluidic channel. We show the amplification effects from both the fluidic circuit and the MOSFET by measuring the translocation of polystyrene beads through the fluidic channel. [Preview Abstract] |
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