Showing papers on "Nanoelectronics published in 2000"

Electronic transport in Y-junction carbon nanotubes

Abstract: Electronic transport measurements were performed on Y-junction carbon nanotubes. These novel junctions contain a large diameter tube branched into smaller ones. Independent measurements using good quality contacts on both individual Y junctions and many in parallel show intrinsic nonlinear transport and reproducible rectifying behavior at room temperature. The results were modeled using classic interface physics for a junction with an abrupt change in band gap due to the change in tube diameter. These Y-junction tubes represent new heterojunctions for nanoelectronics.

Y-junction carbon nanotubes

Abstract: Carbon nanotubes with junctions are considered to be of potential value in nanoelectronics. A simple pyrolysis procedure for producing Y-junction carbon nanotubes is described. The method involves the pyrolysis of the organometallic precursor, nickelocene, along with thiophene at 1273 K. Tunneling conductance measurements showed that at the Y junction, the I-V characteristics are asymmetric with respect to zero bias as in a junction diode.

Laser writing of a subwavelength structure on silicon (100) surfaces with particle-enhanced optical irradiation

Abstract: The field of nanoelectronics has evolved into a major area of investigation. Nanolithographic techniques such as atom beams [1, 2], electron beams [3], scanning probe tunneling [4‐6], and scanning nearfield optical lithography [7‐9] are expected to be potential methods in the fabrication of present and future nanodevices. However, due to their incompatibility with the present fabrication processing and their low throughput, the application of these methods is presently confined to the experimental stage. Meanwhile, traditional optical lithography is limited to the diffraction effect and always relates to complex system and high cost. In this letter, we report a novel, low-cost, and simple optical lithography technique using particleenhanced laser irradiation. Standard spherical silica particles (Duke [10]) packaged as low-residue aqueous suspensions were used in our experiment. The diameter of the particles is 0.5 μ m, with a deviation limited in a range of ∠ 5%. Silicon

Quantum transistors: toward nanoelectronics

Abstract: Electrons that tunnel through insulating barriers and hop on and off minuscule dots are shown to be at the heart of future transistor generations.

Infrared conductivity mapping for nanoelectronics

Abstract: With ever shrinking dimensions in microelectronics, the conductivity performance of charge carriers approaches physical limits and demands tighter control. We show that near-field microscopy carried out at sufficiently long infrared wavelengths—below the plasma frequency—selectively detects and characterizes subsurface mobile carriers with 30 nm resolution, timely for next generation chips as well as for fundamental research, e.g., on low-dimensional electron systems.

Modeling nanoelectronic CNN cells: CMOS, SETs and QCAs

Abstract: Summary form only given, as follows. We investigate the use of nanoelectronic structures in cellular neural network (CNN) architectures, for future high-density and low-power CMOS-nanodevice hybrid circuits. We present simulation results for Single Electron Tunneling (SET) transistors configured as a voltage-to-current transducer for CNN cells. We also present an example of quantum-dot cellular arrays which may be used to realize binary CNN algorithms. Nanoelectronics offers the promise of ultra-low power and ultra-high integration density. Several device structures have been proposed and realized experimentally, yet the main challenge remains the organization of these devices in new circuit architectures. Here, we investigate the use of nanodevices in CNN architectures. Specifically, we focus on nanostructures based on SET devices and Coulomb-coupled quantum-dot arrays, the so-called Quantum-Dot Cellular Automata (QCA). CNN-type architectures for nanostructures are motivated by the following considerations: on the one hand, locally-interconnected architectures appear to be natural for nanodevices where some of the connectivity may be provided by direct physical device-device interactions. On the other hand, CNN arrays with sizes on the order of 1000-by-1000 (which are desirable for applications such as image processing) will require the use of nanostructures since such integration densities are beyond what can be achieved by scaling conventional CMOS devices.

Considerations about Nanoelectronic GSI Processors

Abstract: According to recent studies, the basic technologies presently adopted by the semiconductor industry for memory and processor fabrication should attain limits imposed by the laws of physics around the year 2010. Nanoscale sized devices like single-electron transistors appear as a highly promising option to replace conventional devices by that time. In this study, considerations about the realization of a GSI processor, based upon nanoelectronic devices, are presented.

Role of scanning probes in nanoelectronics: a critical review

Abstract: The continuous downsizing of electronic devices has promoted many ideas of lithography and fabrication techniques at the nanometer scale. Scanning probe lithography (SPL) has been intensively explored as a potential alternative. The conceptual development of the SPL endeavors and their basic mechanisms in the past decade are briefly reviewed. Scaling down the conventional field effect transistors below 30 nm may present enormous technical and economical challenges. Random polarization and fabrication of reproducible lateral tunneling junctions continue to be two major barriers for quantum devices. Instead of trying to compete with other projection type lithographic techniques at the nanometer scale, scanning probes are best suited to explore atom scale devices.

Molecular nanoelectronics

Abstract: Both molecular switching and nanoscale wires have been recently demonstrated. We discuss their possible applications in circuits with emphasis on cross-point memories and programmable logic arrays.

WSe2 nanotubes : Their formation by electron irradiation

Abstract: The discovery of multi-walled carbon nanotubes1 and single-walled carbon nanotubes2 has prompted numerous studies of the structure, properties3,4, and potential applications5,6of these materials. For example, nanotubes are expected to have a high strength-to-weight ratio6, which is advantageous in advanced composites to be used in high performance materials such as aircraft frames. The small dimensions of the tubes show promise for use as a gas absorption medium7, a field emitter for use in flat-panel displays8, and nanoscale electronic devices9.

Toward nanoelectronic systems integration

Abstract: A novel nanometer-scale electronic technology, called nanoelectronics is emerging. Nanoelectronic discrete devices, such as resonant tunneling diodes and transistors, single-electron transistors, bistable quantum-cells, quantum interference devices, etc. have been proposed and built. Technology and physics of the devices are reasonably well understood, but there exists a gap between device physics and nanoelectronic systems integration. In this paper it is shown that in case of local quantum coherence, i.e., if coherence is restricted to the internal dynamics of Coulomb-coupled devices, system dynamics can be described by a set of coupled ordinary nonlinear differential equations. In this case virtual charges, voltages and currents, obeying Kirchoff's equations, can be assigned to the dynamic variables of the state equations, thus circuit models can be introduced. We also show that edge-driven arrays performing ground state computing are locally passive systems if the Coulomb-coupled devices are excited by the input signals only. In order to perform signal processing or computing, external energy should be pumped into the array, and the pumped array should be locally active. Adiabatic pumping is one way of injecting energy to the signal path.

Toward nanoelectronk systems integration

Abstract: A novel nanometer-scale electronic technology, called nanoelectronics is emerging. Nanoelectronic discrete devices, such as resonant tunneling diodes and transistors, singleelectron transistors, bistable quantum-cells, quantum interference devices, etc. have been proposed and built. Technology and physics of the devices are reasonably well understood, but there exists a gap between device physics and nanoelectronic systems integration. In this paper it wiIl be shown that in case of local quantum coherence, i.e. if coherence is restricted to the internal dynamics of Coulombcoupled devices, system dynamics can be described by a set of coupled ordinary nonlinear differential equations. In this case virtual charges, voltages and currents, obeying Kirchoffs equations, can be assigned to the dynamic variables of the state equations, thus circuit models can be introduced. We also show that edge-driven arrays performing ground state computing are locally passive systems if the Coulomb-coupled devices are excited by the input signals only. In order to perform signal processing or computing, external energy should be pumped into the array, and the pumped array should be locally active. Adiabatic pumping is one way of injecting energy to the signal path.

A synthesis of fluid dynamics and quantum chemistry in a diodes momentum-space investigation of molecular wires and

Abstract: Richard Feynman focused on the startling possibilities that would exist at the limit of miniaturization, that being atomically precise devices with dimensions in the nanometer range. “Molecular electronics”, also refered to as “nanoelectronics”, denotes the goal of shrinking electronic devices, such as diodes and transistors, as well as intergrated circuits that can perform logical operations, down to dimensions in the range of 100 nanometers.2 The fortyyear, and growing, hiatus in the development of molecular electronics can be figuratively seen as a period of waiting for the bottom-up and atomically precise construction skills of synthetic chemistry to meet the top-down reductionist aspirations of device physics. The sub-nanometer domain of nineteenth-century classical chemistry has steadily grown, and state-of-the-art supramolecular chemistry can achieve atomic precision in non-repeating molecular assemblies of the size desired for nanotechnology.3 For molecular electronics in particular, a basic understanding of the electron transport properties of molecules themselves must also be developed. The goal of the current research is to investigate the slow (chemically valence) electron dynamics of molecules that are possible prototypes of molecular wires and diode.4 We refrain from basing our analysis on any of the assorted definitions of molecular orbitals. The orbital model was originally devised to explain spectroscopic properties of simple atomic systems in the gaseous phase, a phenomenon far removed from the operation of any kind of