Frontiers in Materials Science, Engineering, and Technology: An FMD Symposium in Honor of Sungho Jin: Process-Property-Performance Correlations: Q-D, 2-D and 3-D Materials & Structures
Sponsored by: TMS Functional Materials Division, TMS: Biomaterials Committee, TMS: Electronic Packaging and Interconnection Materials Committee, TMS: Nanomaterials Committee, TMS: Thin Films and Interfaces Committee
Program Organizers: Fay Hua, Intel Corporation; Tae-Kyu Lee, Portland State University; Young-Ho Kim, Hanyang University; Roger Narayan, UNC/NCSU Joint Department of Biomedical Engineering; Choong-un Kim, University of Texas at Arlington; Nuggehalli Ravindra, New Jersey Institute of Technology

Monday 2:00 PM
February 27, 2017
Room: 33B
Location: San Diego Convention Ctr

Session Chair: Choong-Un Kim, University of Texas - Arlington; Srinivasa Rao Singamaneni, North Carolina State University

2:00 PM Introductory Comments

2:10 PM  Keynote
Direct Conversion of h-BN into c-BN and Formation of Epitaxial c-BN/Diamond Heterostructures: Jagdish (Jay) Narayan1; 1North Carolina State University
    We review the discovery of new phases of carbon (Q-carbon) and BN (Q-BN) and address critical issues of direct conversion of carbon into diamond and h-BN into c-BN at ambient temperatures and pressures in air without any need for catalyst or hydrogen. The Q-carbon and Q-BN are formed as a result of quenching from super undercooled state by using high-power nanosecond laser pulses. We discuss the equilibrium phase diagram (P vs. T) of carbon, and show that by rapid quenching kinetics can shift thermodynamic graphite/diamond/ liquid carbon triple point from 5000K/12GPa to super undercooled carbon at atmospheric pressure in air. Similarly, the hBN-cBN-Liquid triple point is shifted from 3500K/9.5GPa to as low as 2800K and atmospheric pressure. Q-phases exhibit improved mechanical hardness, electrical conductivity, chemical and physical properties, including room-temperature ferromagnetism (RTFM) and enhanced field emission. The undercooled state is quenched into Q-phases or host of nanostructures and thin films.

2:40 PM  Invited
Elastic Coupling between Layers in Two-dimensional Materials: Yang Gao1; Angelo Bongiorno2; Elisa Riedo1; 1City University of New York Advanced Science Research Center,The City College of New York; 2CUNY College of Staten Island
    Two-dimensional materials, such as graphene and MoS2, are films of a few atomic layers in thickness with strong in-plane bonds and weak interactions between the layers. The in-plane elasticity has been widely studied in bending experiments where a suspended film is deformed substantially; however, little is known about the films’ elastic modulus perpendicular to the planes, as the measurement of the out-of-plane elasticity of supported 2D films requires indentation depths smaller than the films’ interlayer distance. Here, we report on sub-ångström-resolution indentation measurements of the perpendicularto- the-plane elasticity of 2D materials. Our indentation data, combined with semi-analytical models and density functional theory, are then used to study the perpendicular elasticity of few-layer-thick graphene and graphene oxide films.We find that the perpendicular Young’s modulus of graphene oxide films reaches a maximum when one complete water layer is intercalated between the graphitic planes. This non-destructive methodology can map interlayer coupling and intercalation in 2D films.

3:10 PM  
Synthesis and Characterization of Nitrogen-vacancy (NV) Centers in Diamond Nanostructure Formed by Laser Annealing Technique: Anagh Bhaumik1; Ariful Haque1; Jagdish Narayan1; 1North Carolina State University
    NV centers in diamond have remarkable optical, electrical and magnetic properties. We report a unique method for synthesis of pure and nitrogen doped nanodiamonds at room temperatures and atmospheric pressure. Amorphous carbon films are deposited onto c-sapphire substrates using pulsed laser deposition (PLD) technique employing KrF nanosecond laser. N doped carbon films are formed by simultaneous bombardment with N2+ (0.5-1.0 KeV) ions using RF plasma. Subsequently, the films are irradiated with nanosecond laser pulses of ArF excimer laser having energy density 0.5-1.0Jcm-2 to form micro and nano structures of diamond. N atoms and vacancies are incorporated in the diamond lattice during the liquid phase growth. SEM, EBSD, Raman spectroscopy, TEM, and EELS are performed to characterize the samples. Electrical pumping of NV centers in diamond is also performed with the application of an external electric field in the presence of 532 nm laser, which have immense application in quantum computing.

3:30 PM Break

3:45 PM  Invited
In-situ TEM Characterization of Nanoscale Systems in Complex Environments: Shen Dillon1; 1University of Illinois at Urbana-Champaign
    Prof. Jin has made great contribution to the development of functional micro and nanoscale systems. Understanding of processes occurring in functional nanoscale systems is often limited by a lack of characterization methods with appropriate spatial and temporal resolution. While many of our advanced nanoscale characterization techniques, like TEM, function best in vacuum, we often wish to characterize systems in liquid or gaseous environments under a variety of stimuli. This talk will highlight our efforts to characterize model nanoscale systems in liquid and gaseous environments under a variety of controlled environmental conditions, such as high and low temperatures, electrochemical, photochemical, and high field.

4:15 PM  Invited
Materials Science in Two Dimensions: Daniel Kaplan1; 1U.S. Army RDECOM-ARDEC
    Recent developments in the synthesis of novel, low-dimensional material systems such as carbon nanotubes, graphene and two-dimensional transition metal dichalcogenides (TMDs) have generated enthusiasm in the scientific community for the promise of applications utilizing unprecedented material properties in the fields of catalysis, photovoltaics, electronics, optoelectronics, and chemical sensing. For example, one such system, molybdenum disulfide (MoS2) has been demonstrated as the channel material for field effect transistors exhibiting high current on/off ratios and low sub-threshold swing. Furthermore, these materials demonstrate compatibility with flexible substrates owing to their unique mechanical properties and the extraction and injection of electrons can be achieved through chemical doping. The electronic properties of monolayered transition metal dichalcogenides may also be tuned via chemical functionalization and nanosheets of tungsten disulfide (WS2) have been demonstrated as efficient catalysts for the hydrogen evolution reaction.

4:45 PM  
Pulsed Laser Deposition of Cubic Boron Nitride Films: Ariful Haque1; Anagh Bhaumik1; Jagdish Narayan1; 1NCSU
    We have synthesized thin films of cubic boron nitride (c-BN) on c-sapphire and r-sapphire substrates using pulsed laser processing technique. A hexagonal boron nitride target was ablated by a pulsed KrF nanosecond excimer laser with 248 nm wavelength. The films were characterized by micro Raman spectroscopy, scanning electron microscopy (SEM), electron back scattered diffraction (EBSD), UV-Vis spectroscopy, and transmission electron microscopy (TEM) techniques. The micro Raman spectra, EBSD patterns, and the electron diffraction patterns from the specimens provide unambiguous evidence of the epitaxial growth of the c-BN phase. By varying the substrate temperature and the laser energy density we have performed a detailed study of microstructures of c-BN. We are able to control the grain size by controlling the growth parameters and we obtained improved epitaxy in the c-BN structures at higher growth temperature and higher energy density of the laser pulses.

5:05 PM  Invited
Quantum Dot Formation In Core-Shell Nanowires: Q. Zhang1; S.H. Davis1; Peter Voorhees1; 1Northwestern University
    Quantum dots embedded within nanowires hold great promise in many quantum photonics applications. Recently, GaAs nanowires have been used as substrates to create novel optoelectronic devices by growing an AlGaAs alloy shell on a GaAs nanowire. The deposition of the AlGaAs layer leads to the spontaneous formation of stripes of Al along certain crystallographic directions and quantum dots near the apex of the shell. A model has been developed for the motion of the faceted AlGaAs-vapor interfaces that accounts for capillarity, deposition, and surface diffusion. We find that for certain combinations of these effects, facets can be present during growth that are not present on the interfacial energy minimizing Wulff shape. These small facets can lead to the formation of Al-rich stripes and quantum dots. The effects of surface diffusion, deposition, and surface energy on the development of stripes of Al and quantum dots will be discussed.