3,613 research outputs found
Enhancing Logic Synthesis of Switching Lattices by Generalized Shannon Decomposition Methods
In this paper we propose a novel approach to the synthesis of minimal-sized lattices, based on the decomposition of logic functions. Since the decomposition allows to obtain circuits with a smaller area, our idea is to decompose the Boolean functions according to generalizations of the classical Shannon decomposition, then generate the lattices for each component function, and finally implement the original function by a single composed lattice obtained by glueing together appropriately the lattices of the component functions. In particular we study the two decomposition schemes defining the bounded-level logic networks called P-circuits and EXOR-Projected Sums of Products (EP-SOPs). Experimental results show that about 34% of our benchmarks achieve a smaller area when implemented using the P-circuit decomposition for switching lattices, with an average gain of at least 25%, and about 27% of our benchmarks achieve a smaller area when implemented using the EP-SOP decomposition, with an average gain of at least 22%
Introduction to Graphene Electronics -- A New Era of Digital Transistors and Devices
The speed of silicon-based transistors has reached an impasse in the recent
decade, primarily due to scaling techniques and the short-channel effect.
Conversely, graphene (a revolutionary new material possessing an atomic
thickness) has been shown to exhibit a promising value for electrical
conductivity. Graphene would thus appear to alleviate some of the drawbacks
associated with silicon-based transistors. It is for this reason why such a
material is considered one of the most prominent candidates to replace silicon
within nano-scale transistors. The major crux here, is that graphene is
intrinsically gapless, and yet, transistors require a band-gap pertaining to a
well-defined ON/OFF logical state. Therefore, exactly as to how one would
create this band-gap in graphene allotropes is an intensive area of growing
research. Existing methods include nano-ribbons, bilayer and multi-layer
structures, carbon nanotubes, as well as the usage of the graphene substrates.
Graphene transistors can generally be classified according to two working
principles. The first is that a single graphene layer, nanoribbon or carbon
nanotube can act as a transistor channel, with current being transported along
the horizontal axis. The second mechanism is regarded as tunneling, whether
this be band-to-band on a single graphene layer, or vertically between adjacent
graphene layers. The high-frequency graphene amplifier is another talking point
in recent research, since it does not require a clear ON/OFF state, as with
logical electronics. This paper reviews both the physical properties and
manufacturing methodologies of graphene, as well as graphene-based electronic
devices, transistors, and high-frequency amplifiers from past to present
studies. Finally, we provide possible perspectives with regards to future
developments.Comment: This is an updated version of our review article, due to be published
in Contemporary Physics (Sept 2013). Included are updated references, along
with a few minor corrections. (45 pages, 19 figures
Testability of Switching Lattices in the Cellular Fault Model
A switching lattice is a two-dimensional array of four-terminal switches implemented in its cells. Each switch is linked to the four neighbors and is connected with them when the switch is ON, or is disconnected when the switch is OFF. Recently, with the advent of a variety of emerging nanoscale technologies based on regular arrays of switches, lattices of multi-terminal switches, originally introduced by Akers in 1972, have found a renewed interest. In this paper, the testability under the Cellular Fault Model (CFM) of switching lattices is defined and analyzed. Moreover, some techniques for improving the testability of lattices are discussed and experimentally evaluated
Logic synthesis and testing techniques for switching nano-crossbar arrays
Beyond CMOS, new technologies are emerging to extend electronic systems with features unavailable to silicon-based devices. Emerging technologies provide new logic and interconnection structures for computation, storage and communication that may require new design paradigms, and therefore trigger the development of a new generation of design automation tools. In the last decade, several emerging technologies have been proposed and the time has come for studying new ad-hoc techniques and tools for logic synthesis, physical design and testing. The main goal of this project is developing a complete synthesis and optimization methodology for switching nano-crossbar arrays that leads to the design and construction of an emerging nanocomputer. New models for diode, FET, and four-terminal switch based nanoarrays are developed. The proposed methodology implements logic, arithmetic, and memory elements by considering performance parameters such as area, delay, power dissipation, and reliability. With combination of logic, arithmetic, and memory elements a synchronous state machine (SSM), representation of a computer, is realized. The proposed methodology targets variety of emerging technologies including nanowire/nanotube crossbar arrays, magnetic switch-based structures, and crossbar memories. The results of this project will be a foundation of nano-crossbar based circuit design techniques and greatly contribute to the construction of emerging computers beyond CMOS. The topic of this project can be considered under the research area of Ăą\u80\u9cEmerging Computing ModelsĂą\u80\u9d or Ăą\u80\u9cComputational NanoelectronicsĂą\u80\u9d, more specifically the design, modeling, and simulation of new nanoscale switches beyond CMOS
CVM: Crossbar-based circuit Verification through Modeling
The implementation of Boolean functions using Nano crossbar-based switching lattices has been suggested as a substitute for conventional CMOS-based approaches in digital circuits. This alternative may satisfy the needs of future electronic designs, considering the expected end of Mooreâs law. This study introduces CVM, a Crossbar-based circuit Verification through Modeling technique.Lattice Science Publication (LSP)
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A Satisfiability-Based Approximate Algorithm for Logic Synthesis Using Switching Lattices
In recent years the realization of a logic function
on two-dimensional arrays of four-terminal switches, called
switching lattices, has attracted considerable interest. Exact
and approximate methods have been proposed for the problem
of synthesizing Boolean functions on switching lattices with
minimum size, called lattice synthesis (LS) problem. However,
the exact method can only handle relatively small instances and
the approximate methods may find solutions that are far from
the optimum. This paper introduces an approximate algorithm,
called JANUS, that formalizes the problem of realizing a logic
function on a given lattice, called lattice mapping (LM) problem,
as a satisfiability problem and explores the search space of the LS
problem in a dichotomic search manner, solving LM problems
for possible lattice candidates. This paper also presents three
methods to improve the initial upper bound and an efficient way
to realize multiple logic functions on a single lattice. Experimental
results show that JANUS can find solutions very close to the
minimum in a reasonable time and obtain better results than
the existing approximate methods. The solutions of JANUS can
also be better than those of the exact method, which cannot be
determined to be optimal due to the given time limit, where the
maximum gain on the number of switches reaches up to 25%.This work is part of a project that has received funding from the
European Unionâs H2020 research and innovation programme under the
Marie SkĆodowska-Curie grant agreement No 691178, and supported by the
TUBITAK-Career project #113E76
Superlattice Nanowire Pattern Transfer (SNAP)
During the past 15 years or so, nanowires (NWs) have emerged as a new and distinct class of materials. Their novel structural and physical properties separate them from wires that can be prepared using the standard methods for manufacturing electronics. NW-based applications that range from traditional electronic devices (logic and memory) to novel biomolecular and chemical sensors, thermoelectric materials, and optoelectronic devices, all have appeared during the past few years. From a fundamental perspective, NWs provide a route toward the investigation of new physics in confined dimensions.
Perhaps the most familiar fabrication method is the vaporâliquidâsolid (VLS) growth technique, which produces semiconductor nanowires as bulk materials. However, other fabrication methods exist and have their own advantages.
In this Account, I review a particular class of NWs produced by an alternative method called superlattice nanowire pattern transfer (SNAP). The SNAP method is distinct from other nanowire preparation methods in several ways. It can produce large NW arrays from virtually any thin-film material, including metals, insulators, and semiconductors. The dimensions of the NWs can be controlled with near-atomic precision, and NW widths and spacings can be as small as a few nanometers. In addition, SNAP is almost fully compatible with more traditional methods for manufacturing electronics. The motivation behind the development of SNAP was to have a general nanofabrication method for preparing electronics-grade circuitry, but one that would operate at macromolecular dimensions and with access to a broad materials set. Thus, electronics applications, including novel demultiplexing architectures; large-scale, ultrahigh-density memory circuits; and complementary symmetry nanowire logic circuits, have served as drivers for developing various aspects of the SNAP method. Some of that work is reviewed here.
As the SNAP method has evolved into a robust nanofabrication method, it has become an enabling tool for the investigation of new physics. In particular, the application of SNAP toward understanding heat transport in low-dimensional systems is discussed. This work has led to the surprising discovery that Si NWs can serve as highly efficient thermoelectric materials. Finally, we turn toward the application of SNAP to the investigation of quasi-one-dimensional (quasi-1D) superconducting physics in extremely high aspect ratio Nb NWs
Minimization of Quantum Circuits using Quantum Operator Forms
In this paper we present a method for minimizing reversible quantum circuits
using the Quantum Operator Form (QOF); a new representation of quantum circuit
and of quantum-realized reversible circuits based on the CNOT, CV and
CV quantum gates. The proposed form is a quantum extension to the
well known Reed-Muller but unlike the Reed-Muller form, the QOF allows the
usage of different quantum gates. Therefore QOF permits minimization of quantum
circuits by using properties of different gates than only the multi-control
Toffoli gates. We introduce a set of minimization rules and a pseudo-algorithm
that can be used to design circuits with the CNOT, CV and CV quantum
gates. We show how the QOF can be used to minimize reversible quantum circuits
and how the rules allow to obtain exact realizations using the above mentioned
quantum gates.Comment: 11 pages, 14 figures, Proceedings of the ULSI Workshop 2012 (@ISMVL
2012
A stable path to ferromagnetic hydrogenated graphene growth
In this paper, we propose a practical way to stabilize half-hydrogenated
graphene (graphone). We show that the dipole moments induced by an
hexagonal-boron nitride (h-BN) substrate on graphene stabilize the hydrogen
atoms on one sublattice of the graphene layer and suppress the migration of the
absorbed hydrogen atoms. Based upon first principle spin polarized density of
states (DOS) calculations, we show that the half hydrogenated graphene
(graphone) obtained in different graphene-h-BN heterostructures exhibits a half
metallic state. We propose to use this new exotic material for spin valve and
other spintronics devices and applications.Comment: 8 pages, 8 figure
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