Bulletin of the American Physical Society
2008 APS March Meeting
Volume 53, Number 2
Monday–Friday, March 10–14, 2008; New Orleans, Louisiana
Session B35: Focus Session: Emerging Materials and Devices I |
Hide Abstracts |
Sponsoring Units: FIAP DMP Chair: Stefan Zollner, Freescale Semiconductor, Inc. Room: Morial Convention Center 227 |
Monday, March 10, 2008 11:15AM - 11:51AM |
B35.00001: The Nanoelectronics Research Initiative and Beyond CMOS Research Activities in the US Invited Speaker: The six leading Semiconductor Companies in the US have joined forces with Federal and State government to form the Nanoelectronics Research Initiative in 2005. The goal is to find new information processing paradigms, systems and devices which will extend Moore's Law functional scaling into the indefinite future. The research activities are guided by 5 central research vectors which define the scope and content of the program and are listed below. \begin{enumerate} \item Computational state variables other than electronic charge \item Non-equilibrium systems out of equilibrium with the thermal environment \item Novel information transport mechanisms \item Nanoscale thermal management \item Directed self assembly of complex heterostructures \end{enumerate} The current NRI research effort consists of 56 projects at 25 universities and 3 research centers in a coherent program where each project is aligned with one or more of the research vectors. During the past two years, significant progress has been made in a number of areas including spin wave, generation, detection and characterization, room temperature DMS materials, femptosecond magnetic domain switching characterization, improved MQCA structures, multiferroic and, magnetoelectric materials and devices, non-conformational metal insulator phase transitions in VO$_{2}$ and ferromagnetic ring nanodevices. A brief discussion and references will be provided. [Preview Abstract] |
Monday, March 10, 2008 11:51AM - 12:03PM |
B35.00002: Diamond Nanoelectronics Igor Altfeder, Jacqueline Krim, Andrey Voevodin Thin films of ultra-nanocrystalline diamond (UNCD) represent an extremely promising nanoelectronic material. The electronic devices based on UNCD can operate at temperatures exceeding by an order of magnitude the working temperature of silicon-based devices. This talk will describe the recent STM/AFM study of CVD-grown UNCD films. The most important advances and challenges of UNCD-electronics, which will be discussed, are (a) the possibility of controlled doping of these films, (b) the influence of doping on chemical structure of UNCD surfaces and interfaces, and (c) exploring extremely low surface adhesion/friction of UNCD for design of MEMS. [Preview Abstract] |
Monday, March 10, 2008 12:03PM - 12:15PM |
B35.00003: Low frequency Noise in Top-Gated Ambipolar Carbon Nanotube Field Effect Transistors Guangyu Xu, Fei Liu, Song Han, Koungmin Ryu, Alexander Badmaev, Chongwu Zhou, Kang L. Wang Low-frequency noise of top-gated ambipolar carbon nanotube field effect transistors (CNT-FET) with aligned CNT growth onto the quartz substrate is presented. The noise of top-gated CNT-FETs in air is lower than that of back-gated devices, and is comparable with that of back-gated devices in vacuum. This shows that molecules in air act as additional scattering sources, which contribute to the noise. Different noise amplitudes in the electron-conduction region and hole-conduction region are due to both the Schottky barriers (SB) with respect to the conduction band and valance band and the scattering in the channel. The SB contact determines the sample conductance, and thus the noise; the channel scattering also determines the noise. The impact of channel length to the noise amplitude is discussed. This device offers a potential low noise CNT-FET structure. [Preview Abstract] |
Monday, March 10, 2008 12:15PM - 12:27PM |
B35.00004: Nanopositioning of Individual Vertical Aligned Carbon Nanotubes on Interconnects Reginald C. Farrow, Amit Goyal, Sheng Liu, Zafar Iqbal, Gordon A. Thomas, Linus A. Fetter Electrophoresis has been used to deposit single wall carbon nanotubes in arrays of sub-100 nm windows in insulating thin films over metal interconnects. The number of nanotubes that are deposited depends on the electric field and the geometry of the windows and nanotubes. Surface charge on the insulator causes the windows to become nanoscopic electrostatic lenses. Under certain readily achievable conditions \textit{only one nanotube will be deposited} at the base of a window since each deposited nanotube modifies the electric field. This discovery enables the process integration of vertical aligned carbon-based electronics with more traditional technologies such as complementary metal oxide semiconductor (CMOS) using the \textit{current generation of lithography and process technology}. Devices such as vertical field effect transistors and interconnected nanoprobe arrays may now be fabricated in the metal levels of CMOS integrated circuits to facilitate three-dimensional polylithic circuit architectures. [Preview Abstract] |
Monday, March 10, 2008 12:27PM - 12:39PM |
B35.00005: Impact Ionization in Photocurrent Measurements of Carbon Nanotube p-n Junctions Nathaniel Gabor, Z. Zhong, K. Bosnick, J. Park, P.L. McEuen We investigate the photocurrent response at a nanotube gated p-n junction using a focused laser illumination source. Scanned photocurrent imaging demonstrates that photocurrent response occurs primarily in the p-n junction. Measurements in an optical cryostat down to 4K reveal large photoresponse and unusual step-like structure in the reverse bias photocurrent. We relate the intersection point of the forward bias photocurrent to the flat band condition in the device and infer the band gap, which is in excellent agreement with the band gap determined by thermal activation and diameter measurements. The striking photocurrent steps in reverse bias occur at intervals roughly equal to the band gap. We attribute these steps to impact ionization and carrier multiplication in the junction region of the device. By measuring the photon energy dependence of the impact ionization process, we determine that ionization occurs with high probability for carriers in the second and higher subbands of carbon nanotubes. These results show that nanotube p-n junctions provide an ideal system for probing carrier dynamics and interactions of electrons and holes in nanotubes. [Preview Abstract] |
Monday, March 10, 2008 12:39PM - 12:51PM |
B35.00006: High Performance Silicon Nanowire Field Effect Transistor Qiliang Li, Xiaoxiao Zhu, Yang Yang, Dimitris Ioannou, John Suehle, Curt Richter We report the fabrication and characterization of double-gated Si nanowire field effect transistors with excellent electrical characteristics and a small subthreshold slope: $\sim $ 85 mv/dec. The Si nanowires were grown by chemical vapor deposition at pre-defined location on a 50 nm thermal SiO$_{2}$ (bottom gate oxide). The source/drain electrodes (Al) were formed by using photolithographic alignment and metal lift-off processes. The nanowires were then covered with HfO$_{2}$ via atomic layer deposition. A thin layer of SiO$_{2}$ was deposited on the HfO$_{2}$ as a buffer layer before the top gate electrode formation (Al, using photolithographic and lift-off processes). This self-aligned process enables the integration of a large number of high-quality nanowire transistors for electronic circuitry. We have investigated the effect of device structure and annealing conditions on the final device performance, and developed theoretical models to assist the device optimization. [Preview Abstract] |
Monday, March 10, 2008 12:51PM - 1:03PM |
B35.00007: Effects of Non-Ideal Edges in Graphene Nanoribbons D. Basu, M.J. Gilbert, L.F. Register, S.K. Banerjee, A.H. MacDonald We report quantum mechanical transport simulations of the edge effects of nanoribbons of two-dimensional (2D) graphite sheets or graphene. Semiconducting graphene nanoribbons have the potential to augment Si technology because of their excellent electronic properties. In practice we find that scattering from the vacant sites in an otherwise perfect armchair edge of graphene reduces its transmission characteristics drastically. These effects decrease as the widths of the ribbons increase and as the number of steps along the edges decrease. However, band gap of these semiconducting graphene decreases as the width increases, leading to an increase in the band-to-band leakage current. We conclude that without atomic precision to define perfect edges, it may not be practical to use very narrow graphene layers as a semiconducting material for field effect transistors (FETs). Our tight-binding treatment of vacancies allows us to study not only FET-like devices, but also the effect of disorder that breaks symmetry in the graphene sheet for more exotic applications such as pseudospin-type devices. [Preview Abstract] |
Monday, March 10, 2008 1:03PM - 1:15PM |
B35.00008: Determination of Non-Accumulative Effects in PCMO Resistive Switches Stephen Tsui, Nilanjan Das, Y.Q. Wang, Y.Y. Xue, C.W. Chu In recent years, the observation of electric field induced resistive switching occurring at the interface between a Ag electrode and Pr$_{0.7}$Ca$_{0.3}$MnO$_{3}$ (PCMO) thin film has stirred a great deal of activity. The controllable switching, depending on the applied voltage polarity, associated with this and other perovskite oxide systems may very well be a means to develop new nonvolatile memory devices. However, a consensus has not yet been reached on the origins of the physical mechanism, be it lattice rearrangement, electromigration, charge trapping, or carrier doping. An important issue is whether the switching behaves in an accumulative fashion, e.g. driven by a change in oxygen stoichiometry through ion-migration. We explore the situation through transport properties, switching characters and the size dependence of the switching area. Our results indicate that a large scale accumulation driven mechanism is not likely for the switching and that a local structural rearrangement may be a more reasonable physical process. [Preview Abstract] |
Monday, March 10, 2008 1:15PM - 1:27PM |
B35.00009: A Physical Model for Resistive Switching In Metal-Oxide Interface Nilanjan Das, Stephen Tsui, Yaqi Wang, Yuyi Xue, Ching-Wu Chu Resistive switching in metal-oxide interface has been studied extensively and different models have been proposed. We have investigated the switch in metal-PCMO ($\Pr_{0.7} Ca_{0.3}MnO_3)$ sample. Interface R and C, both have been found to be frequency independent almost up to 10 MHz. Also the activation energy for both the states (High and Low) are almost the same with bulk as found in R(T) plot. The physical picture will be very shallow potential wells, which may not be enough for retention observed. A pure electronic process (trapping and de-trapping in defects) of carrier only, as suggested earlier, will not be correct answer. [Preview Abstract] |
Monday, March 10, 2008 1:27PM - 1:39PM |
B35.00010: Percolative model for resistance switching S. H. Chang, S. C. Chae, J. S. Lee, S. B. Lee, D.-W. Kim, B. Khang, T. W. Noh There have been research efforts on resistive switching in numerous insulating oxide films for the next nonvolatile memory device. Recently percolation has been considered as a key concept to explain unipolar memory switching [1]. The rupture process of conducting path is closely related to thermal heat budget induced by Joule-heating effect. In this process, the thermal heat dissipation during rupture could play important role in details of unipolar memory switching. In this study, we investigated correlation between the resistance switching behaviors of Pt/NiO/Pt capacitor structures and thermal heat dissipation as a function of the bottom electrode and temperature. Our modified percolative simulation and finite element analysis demonstrated these phenomena. [1] S. C. Chae \textit{et al}., Adv. Mat., to be published (2007). [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