2015 Functional Nanomaterials: Energy and Sensing: Sensing and Electronics II
Sponsored by: TMS Functional Materials Division (formerly EMPMD), TMS: Energy Conversion and Storage Committee
Program Organizers: Jung-Kun Lee, University of Pittsburgh; Behrang Hamadani, National Institute of Standards and Technology ; Sung Hun Wee, HGST, a Western Digital Company; Nitin Chopra, University of Alabama, Tuscaloosa; Terry Xu, The University of North Carolina at Charlotte; Jang-Sik Lee, Pohang University of Science and Technology (POSTECH) POSTECH

Tuesday 2:00 PM
March 17, 2015
Room: Swan 4
Location: Swan

Session Chair: Nitin Chopra, University of Alabama

2:00 PM  Invited
IOM/Mehl Award: The Role of Materials Science in Microelectronics: Past, Present and Future: Subhash Mahajan1; 1University of California Davis
     Every leap in human civilization is associated with a material: stone-, bronze-, and steel-age. Even though the current era is referred to as the information age, it would be apt to call it the Materials Age. This is so because the materials played a crucial role without which the information age may not have been feasible. To illustrate the role of materials science in microelectronics, we have chosen the following examples: Past Role: Zone refining and growth of bulk silicon crystals Present Role: Reduction of dislocations in III-V crystals and degradation behavior of light emitting devices Future Role: Integration of dissimilar materials: two step-step epitaxy of GaN (0001) sapphire; and high temperature electronicsSince the advances in materials are generally accentuated by the technology needs, the field has a bright future.

2:40 PM  
The Role of Structure Directing Agent on the Formation of Copper Nanowires: A DFT Study: Soon Ho Kwon1; Hyuck Mo Lee1; 1KAIST
     Copper nanowires are the promising alternative materials to indium tin oxide(ITO) for transparent electrode because of its high conductivity, good transmittance, and the low cost of fabrication. It has been considered that the structure directing agent (SDA) has important role in the formation of nanowires. Therefore it is essential to understand the effect of SDA, especially ethylenediamine, on a seed of copper nanowires.In this study, we investigated the effect on electronic structure of copper cluster during adsorption of the amine group by density functional theory (DFT) calculation which is suitable to investigate electronic structure of many-body systems. The charge is transferred to the surface atoms of copper cluster and the change of charge distribution can enhance the bonding between surface copper atoms. In addition, the atomic structure of the initial cluster seed and the growth mechanism of copper nanowires were also investigated both theoretically and experimentally.

3:00 PM  Invited
DFT Study of 2D TMD Layers for Device Applications: Santosh KC1; Chenxi Zhang1; Cheng Gong1; Kyeongjae Cho1; 1UT Dallas
     Transition metal dichalcogenides (TMDs) are covalently bound 2D layers stacked together by van der Waals interaction, which can be exfoliated into stable single to few layers. Monolayer MoS2 is direct band gap semiconductor investigated for low-power field effect transistors, and the initial studies have shown promising performance of high on/off current ratio (10^8) and a carrier mobility ~200 cm^2/Vs with a high-κ gate dielectric. Based on these demonstrations, TMDs are considered for tunnel FET (TFET) and ionic memory device applications, which can perform beyond the conventional FET device scaling. To facilitate experimental device material development efforts, we have performed density functional theory (DFT) studies of TMD material properties including band alignments, TMD-metal contacts, TMD-oxide interface, and TMD defect and dopant properties. In this talk, we will discuss the calculated atomic and electronic structure information of TMDs and their implications for nanoscale device applications. This work was supported by the LEAST.

3:40 PM Break

3:55 PM  Invited
Template-free Electrochemical Synthesis of Nanowires and Applications to Nanodevices: Sun Hwa Park1; Hyun Min Park1; Jae Yong Song1; 1Korea Research Institute of Standards and Science
    One-dimensional nanomaterials are generally synthesized by surfactant-assisted or template-based methods. In this talk, it is presented an electrochemical method, which is a low-cost, facile, and template-free process, in order to grow one-dimensional nanostructures. The one-dimensional growth mechanism is unveiled that the filamentary effect in ultra-dilute electrolytes creates an interface anisotropy between nanodeposit and electrolyte, and leads to the one-dimensional growth in the specific direction. The diameters of the one-dimensional nanomaterials are able to be controlled in the range of 80 to 800 nm. The present method can be generally used to grow metals and metal oxides such as Ag, Au, Cu, AgCu, Cu2O, and ZnO nanowires. The electrodeposited nanomaterials are utilized for the applications to anisotropic conductive transparent electrodes, flexible galvanic skin response nanosensors, surface enhanced Raman spectroscopy, thermoelectric devices, anodes of lithium ion batteries, and etc. The template-free electrodeposited nanomaterials are expected to open up further applications in nanotechnology.

4:35 PM  Invited
Anamolus Emission in Organic Conjugated Metal Oxide Nanoparticles: S Seal1; Michael Leuenberger1; Andre Gesquire1; Sanku Mallik2; 1UCF; 2NDSU
    Semiconductor nanoparticles are often used in many energy related applications. When these particles are conjugated with organic- and dye-molecules, yield high efficiency visible photoluminescence (PL). For example, when folic acid is conjugated to nanosize TiO2 and CeO2 particles using specific linkers, a dramatic increase of photoemission intensity is observed. Using density-functional theory (DFT) we demonstrate that the strong increase of the PL can be explained by electronic transitions between the titania surface oxygen vacancy (OV) states and the low-energy excited states of thecomposite molecule anchored onto the surface oxygen bridge sites in close proximity to the OVs. We suggest this scenario to be a universal feature for a wide class of metal oxide nanoparticles, including nanoceria, with a large surface-vacancy density of electronic states and can play a crucial role in electronic and optical properties of nanosystems. The role of this composite system in water-splitting is presented.