1,722,067 research outputs found
Self-limited single nanowire systems combining all-in-one memristive and neuromorphic functionalities
Full text linkThe ability for artificially reproducing human brain type signals’ processing is one of the main challenges in modern information technology, being one of the milestones for developing global communicating networks and artificial intelligence. Electronic devices termed memristors have been proposed as effective artificial synapses able to emulate the plasticity of biological counterparts. Here we report for the first time a single crystalline nanowire based model system capable of combining all memristive functions – non-volatile bipolar memory, multilevel switching, selector and synaptic operations imitating Ca2+ dynamics of biological synapses. Besides underlying common electrochemical fundamentals of biological and artificial redox-based synapses, a detailed analysis of the memristive mechanism revealed the importance of surfaces and interfaces in crystalline materials. Our work demonstrates the realization of self-assembled, self-limited devices feasible for implementation via bottom up approach, as an attractive solution for the ultimate system miniaturization needed for the hardware realization of brain-inspired systems
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Atomic and Molecular Manipulation
No full textThis outstanding textbook provides an introduction to electronic materials and device concepts for the major areas of current and future information technology. On about 1,000 pages, it collects the fundamental concepts and key technologies related to advanced electronic materials and devices. The obvious strength of the book is its encyclopedic character, providing adequate background material instead of just reviewing current trends. It focuses on the underlying principles which are illustrated by contemporary examples.
The third edition now holds 47 chapters grouped into eight sections. The first two sections are devoted to principles, materials processing and characterization methods. Following sections hold contributions to relevant materials and various devices, computational concepts, storage systems, data transmission, imaging systems and displays. Each subject area is opened by a tutorial introduction, written by the editor and giving a rich list of references. The following chapters provide a concise yet in-depth description in a given topic.
Primarily aimed at graduate students of physics, electrical engineering and information technology as well as material science, this book is equally of interest to professionals looking for a broader overview. Experts might appreciate the book for having quick access to principles as well as a source for getting insight into related fields
Oxygen transport in thin oxide films at high field strength
Full text linkIonic transport in nanostructures at high field strength has recently gained attention, because novel types of computer memory with potentially superior properties rely on such phenomena. The applied voltages are only moderate, but they drop over the distance of a few nanometers and lead to extreme field strengths in the MV/cm region. Such strong fields contributes signicantly to the activation energy for ionic jump processes. This leads to an exponential increase of transport speed with voltage. Conventional high-temperature ionic conduction, in contrast, only relies on thermal activation for such jumps. In this thesis, the transport of minute amounts of oxygen through a thin dielectric layer sandwiched between two thin conducting oxide electrodes was detected semi-quantitatively by measuring the conductance change of the electrodes after applyinga current through the dielectric layer. The relative conductance change G/G as a function of current I and duration t follows over several orders of magnitude a simple, empirical law of the form G/G = CIt with fit parameters C, A and B; A,B [0,1]. This empirical law can be linked to a predicted exponential increase of the transport speed with voltage at high eld strength. The behavior in the time domain can be explained with a spectrum of relaxation processes, similar to the relaxation of dielectrics. The influence of temperature on the transport is strong, but still much lower than expected. This contradicts a commonly used law for high-field ionic transport. The different oxide layers are epitaxial with thicknesses between 5 and 70 nm. First large-scale test samples were fabricated using shadow masks. The general behavior of such devices was studied extensively. In an attempt to achieve quantitative results with defect-free, miniaturized devices, a lithographic manufacturing process that uses repeated steps of epitaxial deposition and structuring of the layers was developed. It employs newly developed and optimized wet chemical etching processes for the conducting electrodes. First high-quality devices could be manufactured with this process and confirmed that such devices suffer less from parasitic effects. The lithographically structured samples were made from different materials. The results from the first test samples and the lithographically structured samples are therefore not directly comparable. They do exhibit however in principle the same behavior. Further investigation of such lithographically structured samples appears promising
Electromechanical force microscopy and tip-enhanced Raman spectroscopy for polar oxide nanoparticles
No full textReversible and irreversible polarization processes in ferroelectric ceramics and thin films
No full textModellierung und Simulation der elektrisch-thermisch-mechanisch gekoppelten Eigenschaften keramischer Vielschichtstrukturen
No full textSteuerbare Mikrowellenkomponeneten auf der Basis von ferroelektrischen Dünnschichtkondensatoren
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