2017 Symposium on Functional Nanomaterials: Emerging Nanomaterials and Nanotechnology: Novel Nanomaterials and Techniques
Sponsored by: TMS Functional Materials Division, TMS: Nanomaterials Committee
Program Organizers: Jiyoung Kim, University of Texas; Stephen McDonnell, University of Virginia; Chang-Yong Nam, Brookhaven National Laboratory; V. U. Unnikrishnan, The University of Alabama; Nitin Chopra, The University of Alabama

Monday 8:30 AM
February 27, 2017
Room: Pacific 26
Location: Marriott Marquis Hotel

Session Chair: Jiyoung Kim, University of Texas at Dallas; Chang-Yong Nam, Brookhaven National Lab

8:30 AM Introductory Comments

8:40 AM  Invited
Sequential Infiltration Synthesis (SIS) for Versatile Nanomaterials Fabrication: Seth Darling1; Jeffrey Elam1; 1Argonne National Laboratory
    Sequential infiltration synthesis (SIS) is a new materials growth technique derived from atomic layer deposition (ALD). In SIS, vapor phase precursor molecules are alternately diffused into a polymer film separated by nitrogen purging steps. These precursors are designed to interact with species on the polymer chains such that a cycle of two half-reactions deposits a prescribed and self-limited amount of material within the polymer. Subsequent cycles deposit incrementally larger amounts of inorganic material. Considering the untold variety of molecular precursors, polymeric substrate materials and form factors, and processing conditions, the phase space and applications for SIS have only begun to be explored. Our group is studying applications in environmental remediation, water treatment, energy conversion, and composite materials synthesis, to name a few; as more research groups adopt SIS, the coming years will surely reveal even broader arenas for utilization.

9:10 AM  Invited
Organometallic Infiltration into Polymers toward the Formation of Hybrid Organic-inorganic Nanomaterials: Jesse Jur1; Halil Akyildiz1; Richard Padbury1; 1North Carolina State University
    The infiltration of reactive organometallic vapors into polymers is demonstrated to enable the formation of the hybrid organic-inorganic materials that offers a unique set of optical and mechanical properties. Stemming from observations of reactive infiltration during atomic layer deposition materials growth on polymers, new processes are developed to control the reaction and diffusion of the reactive gases into polymers such as films and fibers. As an example process, we examined the ability to infiltrate trimethylaluminum into polyethylene terephthalate (PET), resulting in a PET-AlOx coordination complex that exhibits increased photoluminescence and photocatalytic activity. Furthermore, the mechanical performance of PET fibers is demonstrated to improve based on the formation of the coordinated complex between polymer chains. This unique set of properties allows for new capabilities in textile structures, including opportunities for fiber-level textile electronic architectures.

9:40 AM  
Direct Patterning Inorganic Nanostructures and Synthesis of Hybrid Materials via Infiltration Synthesis: Chang-Yong Nam1; 1Brookhaven National Laboratory
    Infiltration synthesis is an emerging material synthesis and patterning technique derived from atomic layer deposition, where gaseous organometallic precursors infiltrate polymer template and react to form target inorganic material within organic matrix. This enables the synthesis of inorganic-organic hybrids with enhanced physical properties as well as a direct patterning of inorganic nanostructures. This talk will showcase applications of the method for patterning functioning metal oxide nanostructures based on self-assembled diblock copolymers (BCP) as well as lithographically-defined polymer templates. Various nanopatterns of metal oxides such as AlOx and ZnO could be generated with sub-30 nm feature sizes using BCP patterns, and three-dimensional metal oxide nanostructure with sub-40 nm linewidths and >15 aspect ratios by directly converting lithographically patterned polymer templates. Also discussed are a high-throughput wafer-scale fabrication of in-plane ZnO nanowire field-effect transistor arrays as well as the generation of metal-oxide-infiltrated polymer hybrids with potential multi-functionality and enhanced mechanical properties.

10:00 AM Break

10:20 AM  Invited
Carbon-metal Oxides Nanocomposites by Atomic Layer Deposition: Nicola Pinna1; 1Humboldt-Universitšt zu Berlin
    Atomic layer deposition proved to be a technique of choice for the coating of nanostructured carbon materials. These heterostructures find applications in various areas such as electronics, sensors and energy storage and conversion. Because the chemical inertness of the graphitic carbon inhibits the initiation of ALD film growth, numerous surface functionalization approaches have been investigated in order to provide the required nucleation sites. The different strategies employed for the ALD onto carbon nanotubes, graphene, graphite and other nanostructured carbon materials (e.g. carbon black, fibers) will be described. The peculiarity of ALD for tailoring the chemical, structural and morphological properties of the deposited material will be discussed. Finally, in order to highlight the importance of this class of materials, possible applications in energy storage and conversion, catalysis and gas sensing devices are also reviewed.

10:50 AM  
Ultra-high Elastic Strain Energy Storage in AlOx-infiltrated SU-8 Photoresist Nanopillars: Keith Dusoe1; Aaron Stein2; Chang-Yong Nam2; Seok-Woo Lee1; 1University of Connecticut; 2Brookhaven National Laboratory
    Nanopillars having diameters less than 500nm were lithographically patterned from SU-8 photoresist and underwent sequential infiltration synthesis (SIS) with trimethylaluminum (TMA). A unique composite in which 50nm of the pillar’s surface is an interpenetrating polymer-alumina results from cyclical iterations of SIS. An opportunity for tunability of the elastic properties of the SU-8 polymeric material exists with this fabrication technique by varying the number of infiltration cycles or the organometallic precursor. Mechanical testing of nanopillars was performed using an in-situ nanomechanical testing device in a scanning electron microscope (SEM). SU-8 nanopillars that were infiltrated with 16 cycles of SIS exhibited a high yield strength (500MPa) but an unusually low Young’s modulus (7.5GPa) in uniaxial nanocompression tests. Resilience of this material, as well as its compatibility with lithographic techniques, makes it an appropriate candidate in the design of MEMS devices which require an ultra-high elastic component for advanced actuation and sensor technologies.

11:10 AM  Invited
Bi2Te3 Nanowire Materials and Devices: Interplay between Thermoelectric and Topological Insulators Properties: Kornelius Nielsch1; 1Leibniz Institute for Solid State and Materials Research
    Nanostructuring of thermoelectric materials especially by nanowires geometries was predicted to improve the thermoelectric efficiency, described by the figure of merit ZT = (S2 σ T)/κ (S Seebeck coefficient, σ electrical conductivity, κ thermal conductivity, and T absolute temperature) due to two mechanisms: Enhanced surface scattering of phonons and quantum size effects. Despite all efforts, for Bi2Te3 based nanowires the observed ZT values are significant low compared to bulk values. Recently, it has been demonstrated that Bi2Te3 is a topological insulator exhibiting a highly conductive gapless surface states. This phenomenon can be studied by electrical measurements ideally on single-crystal nanowires due to their high surface-to-volume ratio. We present the synthesis of Bi2Te3 based nanowires with different cross-sections and discuss the relation between topological surface states and their thermoelectric properties. We will finalize the discussion about a recently developed two channel model, which describe the relation between surface and bulk properties.

11:40 AM  
Graphene-ZnO Hybrid with Enhanced Electronic Properties by Atomic Layer Deposition: Myung Mo Sung1; 1Hanyang University
    Large-area graphene films produced by means of chemical vapor deposition (CVD) are polycrystalline and thus contain numerous grain boundaries that can greatly degrade their performance and produce inhomogeneous properties. Grain boundary engineering in CVD graphene is essential to realize graphene in large-scale applications. Here, we report a defect-selective atomic layer deposition (ALD) for stitching grain boundaries of CVD graphene with ZnO so as to increase the connectivity between grains. ALD-ZnO was selectively grown on defect-rich grain boundaries to produce ZnO-stitched CVD graphene with well-connected grains. For the graphene after ZnO stitching, the room-temperature mobility is improved by 5 times (17,007 cm2V-1s-1) at a relatively low carrier density (2.20 ◊ 1012 cm-2), on a par with that of exfoliated, single-crystal graphene. We also demonstrate how ZnO-stitched CVD graphene can be successfully integrated into wafer-scale arrays of top-gated field effect transistors on 4-inch Si and polymer substrates, revealing remarkable device-to-device uniformity

12:00 PM  
1-D, 2-D and 3-D Nanoscale Architectures: Fundamentals, Materials and Applications: Simona Hunyadi Murph1; 1Savannah River National Laboratory & University of Georgia
    Rational assemblies of metallic nanoparticles in one-, two- or three dimensions have become an increasingly attractive method for developing nanoscale architectures for electronics, sensing, and photocatalytic applications. Nanoscale architectures often exhibit improved physical and chemical properties over their single-component counterparts, and hence are potentially useful in a broader range of applications. This presentation will summarize recent advances in the design and fabrication of 1D, 2D and 3D architectures. Metallic nanoparticles, particularly of silver, gold, and platinum and/or various oxides (TiO2, SiO2, Fe2O3) are used as template for creation of complex and ordered nanomaterials with tailored and tunable structural, optical and surface properties. Bottom up and top down approaches are the main key concepts that allows production of nanomaterials and nano-architectures with precisely defined properties and functions. Representative applications pertinent to chemical sensing, environmental and solar fuel applications of these advanced nano-architectures will be described.