Bulletin of the American Physical Society
73rd Annual Gaseous Electronics Virtual Conference
Volume 65, Number 10
Monday–Friday, October 5–9, 2020; Time Zone: Central Daylight Time, USA.
Session GT3: NanomaterialsLive
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Chair: Eva Kovacevic, CNRS University of Orleans |
Tuesday, October 6, 2020 10:00AM - 10:30AM Live |
GT3.00001: Plasma Synthesis of Integrated Graphene Nanoribbons and its Optoelectrical Applications Invited Speaker: Toshiaki Kato We have developed a new, simple, scalable method based on novel plasma catalytic reaction [1-3] for directly fabricating narrow graphene nanoribbons (GNRs) devices on an insulating substrate [4]. Since the establishment of our novel GNRs fabrication method, direct conversion of a Ni nanobar to a suspended GNR is now possible. Indeed, GNRs can be grown at any desired position on an insulating substrate without any post-growth treatment, and the wafer-scale synthesis of suspended GNRs arrays with a very high yield (over 98{\%}) is realized [5]. The growth dynamics of suspended GNRs is also investigated through the systematic experimental study combined with molecular dynamics simulation and theoretical calculations for phase diagram analysis. Unique optoelectrical property, known as persistent photoconductivity (PPC), is also observed in our suspended GNRs devices. By using the PPC, GNRs-based non-volatile memory operation is demonstrated [6]. High thermoelectric performance is also shown in our as-grown suspended GNRs [7]. We believe that our results can contribute to pushing the study of atomically thin layered materials from basic science into a new stage related to the optoelectrical applications [8-11] in industrial scale. [1] T. Kato and R. Hatakeyama, ACS Nano 4 (2010) 7395. [2] T. Kato and R. Hatakeyama, ACS Nano 6 (2012) 8508. [3] B. Xu, T. Kaneko, Y. Shibuta, T. Kato, Scientific Reports 7 (2017) 11149. [4] T. Kato and R. Hatakeyama, Nature Nanotechnology 7 (2012) 651. [5] H. Suzuki, T. Kaneko, Y. Shibuta, M. Ohno, Y. Maekawa, and T. Kato, Nature Communications 7 (2016) 11797. [6] H. Suzuki, N. Ogura, T. Kaneko, T. Kato, Scientific Reports 8 (2018) 11819. [7] Q.-Y. Li, T. Feng, W. Okita, Y. Komori, H. Suzuki, T. Kato, T. Kaneko, T. Ikuta, X. Ruan, K. Takahashi, ACS Nano 13 (2019) 9182. [8] T. Kato and T. Kaneko, ACS Nano 8 (2014) 12777. [9] T. Kato and T. Kaneko, ACS Nano 10 (2016) 9687. [10] T. Akama, W. Okita, R. Nagai, C. Li, T. Kaneko, T. Kato, Scientific Reports 7 (2017) 11967. [11] C. Li, T. Kameyama, T. Takahashi, T. Kaneko, T. Kato, Scientific Reports 9 (2019) 12958. [Preview Abstract] |
Tuesday, October 6, 2020 10:30AM - 10:45AM Live |
GT3.00002: Application of a partially magnetized plasma for graphene hydrogenation. Yevgeny Raitses, Fang Zhao, Christopher Tully The chemical functionalization of two-dimensional materials is an effective method for tailoring their electronical and chemical properties with encouraging applications in energy, catalysis and electronics. Recent experiments on graphene hydrogenation [1] revealed that with the applied magnetic field of 10-50 Gauss, a plasma generated by a DC-RF source of non-thermal electrons at a hydrogen pressure of about 10 mtorr is capable to achieve a high (\textasciitilde 36{\%}) hydrogen coverage without damage on monolayer graphene. Plasma measurements revealed that with the applied magnetic field, the plasma density and the density of hydrogen atoms are much larger than without the magnetic field. The latter explains a high converge observed in the treated 2D material. [1] F. Zhao, Y. Raitses, X. Yang, A.Tan, and C. G. Tully, ``High hydrogen coverage on graphene via low temperature plasma'' submitted to journal (2020). [Preview Abstract] |
Tuesday, October 6, 2020 10:45AM - 11:00AM Live |
GT3.00003: All-gas Phase Plasma Synthesis of Plasmonic Zirconium Nitride for Advanced Photochemistry Applications Christopher Rudnicki, Lorenzo Mangolini, Stephen Exarhos, Alejandro Alvarez Plasmonic nanomaterials absorb light extremely well due to a localized surface plasmon resonance that is correlated with the density of free charge carriers in nanomaterials. Plasmonic nanomaterials have received interest in a variety of fields, such as photocatalysis, photovoltaics, biophotonics, spectroscopy, sensing, and wave-guiding. We present a novel technique using a scalable non-thermal plasma process for the synthesis of plasmonic ZrN with 10 nm rock salt crystallinity determined from XRD and TEM that display a plasmonic peak around 620 nm. Cost and more importantly high thermal stability motivate the search for plasmonic materials alternative to gold and silver, like transition metal-nitrides TiN the relatively unexplored ZrN. A second non-thermal plasma reactor is added downstream to coat the particles in flight with an amorphous silicon nitride layer acting as an oxygen-sink when the material is exposed to atmosphere and yields blue-shifted and increased-intensity absorption. Attractive applications of these plasmonic particles are the reduction of metals using visible light like platinum and chromium (VI) species in water which are extremely toxic. [Preview Abstract] |
Tuesday, October 6, 2020 11:00AM - 11:15AM Live |
GT3.00004: Size Control over Nanocrystalline Gallium Nitride Using Nonequilibrium Plasma Aerotaxy Dillon Moher, Necip Uner, Elijah Thimsen GaN is a semiconductor (SC) of interest due to its wide direct bulk band gap, high stability in many chemical environments, high breakdown voltage, non-toxicity, and high refractive index. We have recently developed a new gas-phase process for the synthesis of free-standing and high-quality III-V SC nanocrystals (NCs) termed nonequilibrium plasma aerotaxy (NPA). For GaN, NPA uses only a gallium source aerosol, nitrogen, and argon in a low-temperature, low-pressure flow through plasma. NC size control has been demonstrated in the range of 5 to 45 nm. Current work seeks to extend control to both smaller and larger size ranges. Particles smaller than 7 nm exhibit size-dependent photoluminescence, emitting in the UVC range, and particles larger than 100 nm can have strong interaction with light for various photonic applications. A combination of approaches was used to make particles larger including manipulating the feed gas composition, increasing the residence time, and pulsing a secondary plasma to cause growth. A secondary mode in the size distribution has evolved which contains a significant fraction of the product mass and is in the size range 75 to 150 nm. The stoichiometry of the large particles and the prospect for making them monodispersed and even larger will be discussed. [Preview Abstract] |
Tuesday, October 6, 2020 11:15AM - 11:30AM Live |
GT3.00005: Tracking Nanoparticle Growth in Pulsed Carbon Arc Discharge Carles Corbella Roca, Sabine Portal, Jiancun Rao, Madhusudhan Kundrapu, Michael Keidar The dynamics of nanoparticle growth in pulsed anodic arc discharge has been studied in time-resolved mode. A fast probe was employed to extract material generated in a pulsed arc plasma held between two graphite electrodes. The probe motion was synchronized with the pulse phase and the exposure time to the plasma was set to 10 ms. The graphite anode was eroded in a Helium atmosphere (300 Torr) by an arc plasma pulsed at 1 Hz with 10{\%} duty cycle, and showing 250 A of peak current. Structure and morphology of the probe depositions were characterized by Raman spectroscopy and scanning electron microscopy. A maximal deposition rate of 260 $\mu $m/s was measured 5 mm away from arc core during the pulse. The deposited layer is rich in carbon nanostructures (graphene platelets, nanotubes). The deposition during the inactive time was several orders of magnitude slower and consisted of amorphous carbon traces. Moreover, the nanoparticle distribution along the collecting probe is correlated with the pulse phase providing thereby information on particle transport. Pulsed nanosynthesis can be modeled as a periodical growth process, where the volume and propagation velocity of the growth region can be adjusted through modulation of the pulse signal waveform. [Preview Abstract] |
Tuesday, October 6, 2020 11:30AM - 11:45AM Live |
GT3.00006: A Numerical Study on Nanoparticle Synthesis in Pulse-Modulated Induction Thermal Plasmas with Intermittent Feedstock Powder Feeding by Method of Moment Yasunori Tanaka, Kazuki Onda, Keita Akashi, Ryudai Furukawa, Yusuke Nakano, Tatsuo Ishijima, Shiori Sueyasu, Shu Watanabe, Keitaro Nakamura We have developed a unique and original method for a high-production rate(\textasciitilde 500 g/h@20 kW) nanoparticle synthesis using pulse-modulated induction thermal plasmas with time-controlled feedstock feeding (PMITP$+$TCFF). The modulated coil current generates an extremely high-temperature thermal plasma in on-time, while a relatively low-temperature plasma in off-time. Feedstock particles are intermittently injected during only on-time synchronously to the PMITP for its efficient evaporation. This evaporated material is cooled down rapidly to promote nucleation of nanoparticles during off-time. In this report, a numerical model was developed for complex phenomena in PMITP$+$TCFF method; A transient electromagnetic thermofluid model was adopted for PMITP with feedstock particle dynamics. Two-way interactions between PMITP and feedstock particles including exchange in mass, momentum and energy were taken into account. For nanoparticle synthesis, the method of moment (MOM) was used to solve general dynamics equation (GDE) for aerosol considering homogeneous nucleation, heterogeneous condensation. As a result, it was found that the coil current modulation can generate modulated thermofluid field by strong induced gas flow, which can promote nucleation of nanoparticles. [Preview Abstract] |
Tuesday, October 6, 2020 11:45AM - 12:00PM Live |
GT3.00007: New Algorithms for Particle-in-Cell Simulations of Carbon Nanotubes Growth in Flowing Plasma. Sergey Averkin Plasma, such as arc discharge plasma, is known as an effective environment for the production of carbon nanotubes (CNTs) and other nanomaterials. It is believed that the plasma-induced production enhancement, relative to conventional chemical vapor deposition reactors, is due to the presence of free radicals and ions that can contribute (along with neutral atoms and molecules) to nanoparticle growth. Numerical simulations of plasma around nanoparticles at kinetic scales can shed light on the underlying physical mechanisms that contribute to nanoparticle growth, thus enabling better prediction and control of nanomaterial production. In this work we present numerical algorithms for simulation of CNT growth in flowing plasmas, as implemented in Tech-X Corporation's commercial particle-in-cell code VSim. We also exercise these algorithms in simulations which explore the effect of the plasma drift velocity on the nanoparticle growth. The new numerical algorithms include extended surface chemistry, efficient remeshing of the simulation domain, and a new formulation of flux boundary conditions based on the Kinetic-Moment boundary condition framework originally developed for the Direct Simulation Monte Carlo (DSMC) method. [Preview Abstract] |
Tuesday, October 6, 2020 12:00PM - 12:15PM Live |
GT3.00008: Titanium nitride nanocrystal with a silicon oxynitride shell: an alternative material to gold for high temperature applications Lorenzo Mangolini, Carla Berrospe Rodriguez, Alejandro Alvarez Barragan, Stephen Exarhos, Giorgio Nava The study of plasmonic nanomaterials like gold has been widely investigated due to their controllable optical properties and ease of production at a lab-scale level. However, due to their poor thermal stability and high cost, scienties have researched alternative plasmonic materials to overcome these. Titanium nitride (TiN) has considerably higher thermal stability than noble metals, high free carrier densities and display plasmonic properties in the visible to the near infrared (NIR) spectrum, which makes it suitable for biomedical applications. Despite the advantages of TiN, this material is susceptible to oxidation which degrades its high absorption response. We performed a comparative study between bare and core-shell TiN nanoparticles, with respect to their structural, chemical, and optical properties. These particles were synthesized in a non-thermal plasma reactor system, where TiN nanocrystals are nucleated in a first reactor and uniformly coated with silicon nitrate in a second reactor. We found that oxidation due to air exposure was reduced by the coating and significantly improves the plasmonic response of TiN. Finally, thin films with the core-shell structures presented no significant changes in their plasmonic response after being exposed to an inert atmosphere heated up to 900\textdegree C. These results provide a deeper insight of the nitride-based plasmonic material's potential for high temperature applications, which overcomes the limitations of gold. [Preview Abstract] |
Tuesday, October 6, 2020 12:15PM - 12:30PM On Demand |
GT3.00009: Synthesis of Cerium Oxide Nanoparticles by Atmospheric-pressure Pulsed Discharge Plasma Wanying Zhu, Wahyu Diono, Hideki Kanda, Motonobu Goto Cerium oxide nanoparticles have attracted much attention because of their excellent catalytic activities, which have been used in various fields. Various methods to synthesize cerium oxide nanoparticles have been reported, such as hydrothermal, solvothermal, thermal decomposition. In this work, a novel method is proposed using atmospheric-pressure pulsed discharge plasma in a slug flow capillary reactor system, which has a low operating cost and easy implementation. In the slug flow capillary reactor system, liquid-gas motion was generated in a glass capillary tube by flowing feed solution and argon gas simultaneously. The bipolar pulsed output voltage (10 kV) was applied to the bubble motion via the copper plate attached to the glass tube surface. Cerium nitrate or ammonium cerium nitrate solution was used as feed solution. The produced cerium oxide nanoparticles were characterized by transmission electron microscopy (TEM). Different stabilizers were used to prevent nanoparticles aggregation, including starch, proline, and glycine. Catalytic activities of products are also investigated by photocatalytic degradation of methylene blue in aqueous solution under UV light conditions. [Preview Abstract] |
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