2017 Symposium on Functional Nanomaterials: Emerging Nanomaterials and Nanotechnology: Nanomaterials Generals
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

Wednesday 2:00 PM
March 1, 2017
Room: Pacific 24
Location: Marriott Marquis Hotel

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


2:00 PM  
In Situ Heating Experiments in the TEM on Silver Nanocrystals: Sriram Vijayan1; Sravan Thota1; Jing Zhao1; Mark Aindow1; 1University of Connecticut
    Modern micro-electro-mechanical system (MEMS) based in situ TEM heating stages give far less thermal lag between the heater and sample, and much lower drift rates, than conventional heating stages in which a conventional sample is heated by conduction from the specimen cup. These advantages accrue from the close proximity of the on-chip coils to the sample support membrane, and the very small total mass of material being heated. While thermal gradients are all but eliminated in MEMS-based stages, the small sample volume makes the measurement of sample temperature very challenging. One possible solution is to exploit the Kelvin effect in which the sublimation temperature of nanoparticles depends on the nanoparticle size. Here we report a study in which the sublimation of PVP-capped Ag nano-cubes with a monomodal size distribution has been used to calibrate the temperature of an FEI Nano Ex- i/V MEMS-based in situ TEM heating stage.

2:20 PM  Student
FT-IR Investigation of H Content in SiNX Thin Film Grown by PEALD Using HCDS as Precursor; Achieving Low WER: Harrison Kim1; Young-Chul Byun1; Xin Meng1; Jiyoung Kim1; B. K. Hwang2; 1The University of Texas at Dallas; 2Dow Corning Corporation
     We investigated the relationship between the chemical resistance properties of SiNX and H content determined by Fourier Transform Infrared Spectrometry (FT-IR). Improving the chemical resistance property of SiNX while maintaining electrically insulating properties is of high importance to industry.We adopted plasma-enhanced atomic layer deposition (PEALD) since the technique is best suited for growing high quality thin films at sufficiently low temperatures to be usable in modern CMOS fabrication. SiNX were grown using hexachlorodisilane (HCDS) as a Si precursor and N2 plasma as a nitrogen source. Chemical resistance was evaluated by calculating the wet etch rate (WER). FT-IR was then adopted to correlate the H content with the WER. It was found that SiNX films having a similar relative H content had a similar WER, regardless of the film thickness. This correlation indicates that simple FT-IR analysis can be adopted as an effective tool for characterizing the quality of SiNX.

2:40 PM  
Effects of Surface Treatments on the Electrical Characteristics of AlGaN/GaN MOS Capacitors Using ALD Grown Epitaxial ZnO as Interfacial Gate Dielectric: Xin Meng1; Young-chul Byun2; Jaegil Lee2; Jiyoung Kim2; 1University of Texas Dallas; 2Univeristy of Texas Dallas
    GaN based MOS-HEMTs have attracted enormous attention for power electronics applications. Various techniques (e.g. in-situ plasma treatment, wet cleaning, etc.) have been implemented to improve quality of gate dielectric/barrier interface. In this work, lattice-matched epitaxial ZnO grown by ALD is proposed as interfacial gate dielectric on AlGaN/GaN. Improved dielectric/barrier interface is expected because of similar band gap (~3.4 eV) and small lattice misfit (~1.8%) between wurtzite ZnO and GaN. This oxide layer also serves as a transition layer prior to high-k dielectrics growth by ALD. Surface treatments are quite critical to achieve good interface quality and outstanding device performance. Several treatment techniques (e.g. plasma treatment, wet cleaning, etc.) are evaluated by electrical characterization (C-V) of simple AlGaN/GaN MOS capacitors. This work was supported by the IT R&D program of MOTIE/KEIT ("Grant No. 10048933, Development of epitaxial structure design and epitaxial growth system for high-voltage power semiconductors").

3:00 PM  
The Effect of H2O vs. O3 as the ALD Oxidant on the Ferroelectric Phase Transition of Hafnium – Zirconium Oxide: Dushyant Narayan1; Si Joon Kim1; Jae-Gil Lee1; Young-Chul Byun1; Joy Lee1; Antonio Lucero1; Scott Summerfelt2; Jiyoung Kim1; 1The University of Texas at Dallas; 2Texas Instruments
    In this study, we explore the effect of H2O and O3 as the atomic layer deposition (ALD) oxidant on the ferroelectric phase transition in hafnium-zirconium oxide. Hafnium oxide based ferroelectric materials have attracted considerable attention for their use in memory technologies due to an inherent advantage in scalability. One outstanding issue for the widespread adoption of hafnium-zirconium oxide in industry is understanding and controlling the ferroelectric phase transition in poly-crystalline ALD films. Previous results on dielectric hafnium oxide ALD using H2O and O3 indicate that other electrical properties are affected by the presence of carbon and hydrogen impurities. We find that H2O based ALD ferroelectric hafnium-zirconium oxide films when integrated into MIM capacitor structures show significant deterioration in remnant polarization and endurance as well as an increase in the coercive field in contrast with O3 based films.

3:20 PM Break

3:40 PM  
Gas Condensation of Fe65Co35-Ag/Au Core-Shell Nanoparticles for Biomedical Applications: Mark Koten1; Marlann Patterson2; Jeffrey Shield1; 1University of Nebraska - Lincoln; 2University of Wisconsin - Stout
    Many of the magnetic nanoparticles that make up the cores of nanocomposites studied for magnetic separation or cancer thermotherapy are superparamagnetic, which have the benefit of not agglomerating in solution, but also have a weaker response to external magnetic fields. Fe65Co35 (Permendur) is a well-known soft magnetic alloy with one of the highest magnetic moments of today’s alloys (240 emu/g). The many benefits of using Ag and Au components in nanosystems are well known. They can passivate inorganic core materials, offer functional surfaces for cellular labelling, and enable the prospect of photothermal imaging in the near infrared range. Building on recent advancements in the gas condensation of core-shell nanoparticles, large quantities of Fe65Co35-Ag and Fe65Co35-Au core-shell nanoparticles have been fabricated. The primary driving force for the core-shell configuration is the difference in surface energy between the magnetic elements (2.5 – 3.2 J/m2) and noble metals (1.2 – 1.5 J/m2).

4:00 PM  Cancelled
Thermal and Electrical Transport in Glassy Carbon Nanowires: Laia Ferrer-Argemi1; Arnoldo Salazar1; Marc Madou1; Jaeho Lee1; 1University of California Irvine
    The development of cost-effective nanomaterial based devices has renewed interest in glassy carbon because it is easy to fabricate photoresist structures and they can be carbonized to obtain a conductive stiff structure of glassy carbon. However, glassy carbon thermal transport has received relatively little attention, particularly at the nanoscale. We create glassy carbon nanowires by electrospinning of SU-8 fibers, which provide suspended wires in a continuous configuration with no contact resistance. The nanowire diameter is controlled by processing parameters, such as electrospinning velocity and voltage, down to tens of nanometers. We measured the thermal and electrical conductivity of the nanowires both in DC and the 3-ω method to obtain accurate thermal measurements. The data matches with simulation results based on finite element modeling. The temperature dependence of the electrical properties agrees well with theoretical models based on hopping and thermally-activated electron transport. With this, we predict the devices thermal behavior.

4:20 PM  
Synthesis and Consolidation of Nanocrystalline Bulk Aluminum Nitride: Matthew Duarte1; Yasuhiro Kodera1; Javier Garay1; 1University of California San Diego
    Aluminum nitride (AlN) is a ceramic material with outstanding properties such as high thermal conductivity, high electrical resistivity and low thermal expansion coefficient. Although AlN exhibits high stability in inert envelopments, it shows high reactivity under the presence of water and oxygen. Therefore, obtaining pure AlN nano powder and bulk nanocrystalline ceramics is challenging. Here we present the success of bulk nanocrystalline AlN prepared through gas-nitridation (GN) and Current Activated Pressure Assisted Densification (CAPAD). The former process was able to synthesize AlN powder with grain sizes below 100 nm from oxide precursors. Processing parameters of GN such as time and temperature were studied. The latter process succeeded to produce bulk AlN (>97% theoretical density). Nano AlN powder shows higher densification kinetics compared with microcrystalline powders. The X-Ray diffraction and SEM analysis showed the crystallite size and the grain size of the bulk were below 100 nm.

4:40 PM  
Plasmon Induced Interfacial Engineering of Nanowires Heterojunctions for Nanoelectronics with Femtosecond Laser Radiation: Luchan Lin1; Lei Liu1; Guisheng Zou1; Walt Duley2; Y.Norman Zhou1; 1Tsinghua University; 2University of Waterloo
    Surface plasmon resonance (SPR) which arises from the collective electron oscillation can generate intense heat input and electromagnetic force. And this plasmonic effect is locally constraint by the nanostructures, especially at those structural discontinuities. Due to the high pulse energy of femtosecond laser, materials can be modified under strong localized energy input, where melting, ablation, even materials evolution can occur. And among nanowires structures with different geometries and dielectric environment, interconnection as well as interfacial engineering due to localized plasmonic effect happened to achieve functional electronic nanowires units which shows potential applications like nanowire rectifiers or memristors. Due to the interfacial engineering at the heterojunctions, electrical barrier can be modified to achieve different contact conditions which can achieve controllable electrical response. And this selective energy input in nanowires structures due to localized plamonic effect under scalable laser radiation shows facile technique to modify nanowires heterojunctions for nanoelectronics.