Bulletin of the American Physical Society
APS March Meeting 2014
Volume 59, Number 1
Monday–Friday, March 3–7, 2014; Denver, Colorado
Session J44: MEMS, NEMS, and Mechanical Properties |
Hide Abstracts |
Sponsoring Units: FIAP Chair: Ichiro Takeuchi, University of Maryland Room: Mile High Ballroom 4C |
Tuesday, March 4, 2014 2:30PM - 2:42PM |
J44.00001: All-thin-film PZT/FeGa Multiferroic Cantilevers and Their Applications in Switching Devices and Parametric Amplification Yi Wang, Tiberiu-Dan Onuta, Chris Long, Samuel Lofland, Ichiro Takeuchi We are investigating the characteristics of microfabricated PZT/FeGa multiferroic cantilevers. The cantilevers can be driven by AC or DC magnetic and electric field, and the device response can be read off as a piezo-induced voltage. We can use the multiple input parameters to operate the devices in a variety of manners for different applications. They include electromagnetic energy harvesting, pulse triggered nonlinear memory devices, and parametrically amplified ME sensors. Due to the competition of anisotropy and Zeeman energies, the mechanical resonant frequency of the cantilevers was found to follow a hysteresis behavior with DC bias magnetic field applied in the cantilever easy axis. We can also control and tune the occurrence of nonlinear bifurcation in the frequency spectrum. The resulting hysteresis in the frequency spectrum can be used to make switching devices, where the input can be DC electric and magnetic fields, as well as pulses of AC fields. We have also demonstrated parametric pumping of the response from an AC magnetic field using frequency-doubled AC electric field. The enhanced equivalent ME coefficient is as high as 10 million V/(cm*Oe), when the pumping voltage is very close to a threshold voltage. The quality factor also increases from 2000 to 80000 with pumping. [Preview Abstract] |
Tuesday, March 4, 2014 2:42PM - 2:54PM |
J44.00002: Rotational Modes in Phononic Crystals Ying Wu, Pai Peng, Jun Mei We propose a lumped model for the rotational modes in two-dimensional phononic crystals comprised of square arrays of solid cylindrical scatterers in solid hosts. The model not only can reproduce the dispersion relations in a certain range with one fitted parameter, but also gives simple analytical expressions for the frequencies of the eigenmodes at the high symmetry points in the Brillouin zone. These expressions provide physical understandings of the rotational modes as well as certain translational and hybrid mode, and predict the presence of accidental degeneracy of the rotational and dipolar modes, which leads to a Dirac-like cone in the Brillouin zone center. [Preview Abstract] |
Tuesday, March 4, 2014 2:54PM - 3:06PM |
J44.00003: Fracture and Failure of Nanoparticle Monolayers and Multilayers Yifan Wang, Pongsakorn Kanjanaboos, Edward Barry, Sean Mcbride, Xiao-Min Lin, Heinrich Jaeger We present the first systematic investigation of fracture in self-assembled gold nanoparticle mono- and multilayers, attached to elastomer substrates and subjected to tensile stress. Imaging the fracture patterns down to the scale of single particles provides detailed information about the crack width distribution and allows us to compare the scaling of the average crack spacing as a function of strain with predictions by shear-lag models. With increasing particle size, the fracture strength is found to increase while it decreases as the film thickness is built up layer by layer, indicating stress inhomogeneity and crack propagation in the thickness dimension. [Preview Abstract] |
Tuesday, March 4, 2014 3:06PM - 3:18PM |
J44.00004: Elastic Properties of Graphene Nanomeshes Ashwin Ramasubramaniam, Corinne Carpenter, Andre Muniz, Dimitrios Maroudas We report results on the elastic properties of graphene nanomeshes following a systematic analysis based on molecular-statics and molecular-dynamics simulations of uniaxial tensile deformation tests according to reliable bond-order classical interatomic potentials. Elastic properties are determined as a function of the nanomesh architecture, including the regular arrangement of pores in the nanomesh (pore lattice structure), pore morphology, nanomesh density ($\rho$), and pore edge passivation. We report scaling laws for the density dependence of the elastic modulus $M$ and find that $M$ scales with the square of the density, consistently with other cellular materials, for circular unpassivated pores over the range of temperature and nanomesh architectural parameters examined. We find that pore edge passivation strengthens the elastic moduli. The effects of passivation and pore morphology, namely, the aspect ratio of elliptical pores, on the $M(\rho)$ scaling laws are analyzed in detail. [Preview Abstract] |
Tuesday, March 4, 2014 3:18PM - 3:30PM |
J44.00005: Scattering of Gigahertz Coherent Acoustic Phonons by Nanoporous Structures in Hypersonic Crystals Gaohua Zhu, Gary Wiederrecht, Songtao Wu, Debasish Banerjee, Kazuhisa Yano A gigahertz acousto-optic modulation technique, based on a mechanism in which the perturbation of the photonic band gap is caused by the coherent oscillation of the phonon modes in the hypersonic crystal, is demonstrated. We present the measurement results of the coherent acoustic vibrations of the hypersonic crystals comprised of SiO$_{2}$ or nanoporous SiO$_{2}$ spheres. Our transient reflection spectroscopy results identify the different transport behaviors of acoustic waves in the hypersonic crystals. While the bulk phonon waves are heavily damped by the nanoporous structures in the hypersonic crystal, the decay time of the surface phonon wave is barely affected. [Preview Abstract] |
Tuesday, March 4, 2014 3:30PM - 3:42PM |
J44.00006: High-density aerogels with ultralow sound velocity: Microstructure is a key parameter determining the sound velocity Ai Du, Bin Zhou, Yang Shen, Qiujie Yu, Jun Shen Aerogels are more and more regarded as a new state of matter nowadays because of its diverse chemical compositions and unique properties which could fill the gap between condensed matter and gas-state matter. Among the properties, the ultralow sound velocity in the aerogels (lower than that in the air) is of great interests. J. Fricke's group studied many kinds of aerogels with different compositions and found that the sound velocity was mainly influenced by the density. Thus they obtained the lowest sound velocity result ($\sim$ 100 m/s) in a low-density silica aerogel medium ($\sim$ 0.05 g.cm$^{-3})$. Here we studied the acoustical properties of the aerogels with the similar high density (about 1.3 g.cm$^{-3})$ but different skeleton structure (nano-, micro- or nano-/micro- structured) by adjusting the phase separation mode. The sound velocities of all the aerogels are below 300 m.s$^{-1}$, among which micro-/nano- structured aerogel exhibits lowest longitudinal wave velocity (below 80 m.s$^{-1})$. Further structural studies indicated that the hierarchical arrangement of microstructure is the key parameter determining the sound velocity besides the density. [Preview Abstract] |
Tuesday, March 4, 2014 3:42PM - 3:54PM |
J44.00007: Absolute surface energies, fracture toughness, and cracking in nitrides Cyrus E. Dreyer, Anderson Janotti, Chris G. Van de Walle Growth of high quality single crystals and epitaxial layers of GaN is critical for producing high-efficiency optoelectronic and power electronic devices. One of the fundamental material properties that govern growth of single crystals is the absolute surface energy of the crystallographic planes. Knowledge of these energies is required to understand and optimize growth rates of different facets in GaN, and provide fracture toughnesses for brittle fracture. By means of hybrid functional calculations, we have determined absolute surface energies for the non-polar \{11-20\} $a$ and \{10-10\} $m$ planes, and approximated values for polar (0001) $+c$ and (000-1) $-c$ planes in wurtzite GaN. For all surfaces, we consider low-energy bare and hydrogenated reconstructions under a variety of conditions relevant to experimental growth techniques. We find that the energies of the m and a planes are similar, and constant over the range of conditions studied. In contrast, the energies of the polar planes are strongly condition dependent. Even so, we find that the $+c$ polar plane is systematically lower in energy than the $-c$ plane. We have used our surface energies to determine brittle fracture toughnesses in AlN and GaN, as well as the critical thickness for cracking of AlGaN on GaN. [Preview Abstract] |
Tuesday, March 4, 2014 3:54PM - 4:06PM |
J44.00008: Cryogenic Nano-Fabrication using the Fab on a Chip approach Matthias Imboden, Han Han, Thomas Stark, Evan Lowell, Jackson Chang, Flavio Pardo, Cristian Bolle, Pablo del Corro, David Bishop The Fab on a Chip approach is a novel fabrication technique that leverages the control and stability of MEMS machines to fabricate structures on the nano-scale. This contrasts to standard deep-UV and e-beam lithography methods typically used today. We present how a fully functional nano-fabrication system can be operated in a cryostat to enable novel physics experiments. To this end MEMS based machines are built that mimic typical macroscopic tools found in a modern nano-fabrication facility. We demonstrate functioning film thickness monitors, heaters, shutters and atom flux sources that can all be integrated on a single silicon chip. At the heart of the fab is a dynamic shutter-aperture system that functions as a programmable stencil which guides atoms to specific locations at precise times. It is argued that this method has the potential to obtain single atom control of the deposited materials. The low power and small footprint enables the setup to function in a cryogenic environment. We demonstrate basic functionality of the elements at liquid helium temperatures. The advantage of resist free lithography and the deposition being the final fabrication step is the ability to pattern materials incompatible with standard techniques. Furthermore, the ultra-clean environment is suited for high purity fabrication of structures made of exotic materials such as lithium, with the intent to enable novel electron transport experiments. [Preview Abstract] |
Tuesday, March 4, 2014 4:06PM - 4:18PM |
J44.00009: Integrated MEMS mass sensor and atom source for a ``Fab on a Chip'' Han Han, Matthias Imboden, Thomas Stark, David Bishop ``Fab on a Chip'' is a new concept suggesting that the semiconductor fabrication facility can be integrated into a single silicon chip for nano-manufacturing. Such a chip contains various MEMS devices which can work together, operating in a similar way as a conventional fab does, to fabricate nano-structures. Here we present two crucial ``Fab on a chip'' components: the MEMS mass sensor and atomic evaporation source. The mass sensor is essentially a parallel plate capacitor with one suspended plate. When incident atoms deposit on the suspended plate, the mass change of the plate can be measured by detecting the resonant frequency shift. Using the mass sensor, a mass resolution of 3 fg is achieved. The MEMS evaporation source consists of a polysilicon plate suspended by two electrical leads with constrictions. By resistively heating the plate, this device works as a tunable atom flux source. By arranging many of these devices into an array, one can build a multi-element atom evaporator. The mass sensor and atom source are integrated so that the mass sensor is used to monitor and characterize the atomic flux. A material source and a sensor to monitor the fabrication are two integral components for our ``Fab on a Chip.'' [Preview Abstract] |
Tuesday, March 4, 2014 4:18PM - 4:30PM |
J44.00010: Measurement of Casimir Force between Monolithic Silicon Microstructures Lu Tang, Ho Bun Chan, Jie Zou, Zsolt Marcet, Yiliang Bao, Alejandro Rodriguez, Homer Reid, Alexander McCauley, Steven Johnson, Ivan Kravchenko We present measurements of the Casimir force between silicon components in a near-planar geometry. We create the device from a silicon-on-insulator wafer using microfabrication. It contains a force-sensing micromechanical beam and an electrostatic comb actuator for controlling the distance. The two lithographically-defined micromechanical components are on the same silicon substrate and are automatically aligned after fabrication. Thus, we can achieve a high degree of parallelism between the two interacting surfaces. We employ a magneto-motive technique to measure the shift in the resonance frequency of the force sensing beam. Periodic Lorentz forces are exerted on the beam when an ac current is applied in a perpendicular magnetic field. As the movable electrode is pushed towards the silicon beam by the comb drives, the Casimir force increases. The force gradient is proportional to the resonance frequency shift of the beam. After the calibration using electrostatic forces and balancing the residual voltage, we measure the Casimir force gradient. Our results are in reasonable agreement with theoretical calculations, considering possible contributions of patch potentials. Apart from providing a compact platform for Casimir force measurements, this scheme also opens new opportunities for the measurement of Casimir force in complex geometries. [Preview Abstract] |
Tuesday, March 4, 2014 4:30PM - 4:42PM |
J44.00011: Silicon Nanomembrane Bipolar Junction Transistors for Microwave Frequency Applications John Bavier, Vince Ballarotto, John Cumings Silicon nanomembranes (SiNMs) are a promising material for flexible semiconductor devices due to their high carrier mobility and compatibility with standard CMOS processing. Previous studies have reported SiNM field-effect transistors with operating frequencies as high as 12 GHz. In order to expand the utility of SiNM devices, a method for the fabrication of monocrystalline microwave frequency silicon bipolar junction transistors (BJTs) will be presented. High-temperature processing of SiNM BJT devices is performed on a Silicon-on-Insulator (SOI) wafer. Using angled ion implantation, conformal chemical vapor deposition and anisotropic reactive ion etching, a poly-silicon sidewall spacer is formed. This spacer defines a base region approximately 200nm wide without the use of electron beam lithography. Devices are then released using selective wet etching in HF and transferred to alternate flexible substrates. Microwave frequency data will be presented, and the effects of the transfer process on device performance will be discussed. [Preview Abstract] |
Tuesday, March 4, 2014 4:42PM - 4:54PM |
J44.00012: ABSTRACT WITHDRAWN |
Tuesday, March 4, 2014 4:54PM - 5:06PM |
J44.00013: Microelectromechanical Systems (MEMS) for Tunable Plasmon Coupling Thomas Stark, Matthias Imboden, Sabri Kaya, Shyamsunder Erramilli, Ahmet Yilmaz, Alket Mertiri, Jackson Chang, David Bishop, Selim Unlu The plasmonic response of metallic nanoparticles depends upon the particle composition, size, shape, surrounding medium, and electromagnetic field coupling to neighboring particles. We present schemes for using MEMS to tune the separation of plasmonic elements and thereby alter the plasmonic response. One of our devices can move two nanoparticles along three axes, creating a dimer with a tunable separation. Localized surface plasmon resonances are sensitive to changes in the surrounding dielectric medium, a phenomenon that has been used in sensing applications [1]. We will use the dimer as a tunable sensor by scanning it through a region of interest and extrapolating changes in the local dielectric properties from the shift in the plasmonic resonance. Another MEMS device actuates arrays of micron-sized gold antennas relative to one another. Changing the separation between elements in an array of plasmonic particles can lead to electromagnetically induced transparency (EIT) and absorption (EIA) [2]. We will shift the arrays relative to one another and measure the spectral response using Fourier transform infrared spectroscopy to demonstrate EIT and EIA. [1] Mock, J., Et al. Nano Lett. 3 (4), 485-491 (2003). [2] Adato, R., et. al., Nano Lett. 13 (6), 2584-2591 (2013). [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700