1,720,979 research outputs found
Two-Dimensional MoS2 Logic Inverter
No full textInverters are crucial in digital electronics as building blocks of logic circuits. The overall functionality of integrated circuits strongly depends on the performance of their components, whose continuous improvement is a key area of research. However, conventional inverter circuits, typically based on bulk semiconductors, face several limitations, including limited scalability, increasing power consumption, and significant transit time. Two-dimensional (2D) materials
with unique electrical properties offer a potential solution to overcome these constraints. In this work, we fabricate and investigate the electrical properties of a resistive load inverter entirely based on molybdenum disulfide (MoS2). A thinner MoS2 flake is used as the channel of the inverter’s driver transistor, exhibiting an n-type behaviour with a high ION/IOFF ratio of 107 and mobilities up to 19 cm2 V-1 s-1 for Vds = 1 V. The resistive load of the circuit consists of a thicker flake, which demonstrates lower gate tunability and higher conductivity.
Specifically, it shows an ION/IOFF ratio smaller than 103 and mobility as high as 34 cm2 V-1 s-1 for Vds = 1 V. The inverter presents a maximum output voltage Vmax = 1 V and a minimum
output voltage Vmin = 0.65 V. It is also characterized by large noise margins, NML = 0.94 V and NMH = 0.65 V. Moreover, a possible strategy to enhance the inverter efficiency is discussed
by analyzing different load resistances. This work highlights MoS2-based inverters as a promising step toward low-power and scalable nanoelectronics
Metal-semiconductor Schottky diode with Landauer’s formalism
No full textThe Schottky barrier diode is a unipolar electronic device formed by the heterojunction of a metal and a semiconductor, widely used in various electronic and optoelectronic applications. Its rectifying current–voltage characteristic is typically derived using thermionic emission theory, which describes the transport of carriers over the Schottky barrier formed at the metal-semiconductor interface. In this paper, after briefly reviewing the metal-semiconductor heterojunction fundamentals and Landauer’s approach to electric transport, we propose an alternative way to derive the current–voltage behavior of a Schottky diode using Landauer’s formalism. This derivation can be directly applied to Schottky contacts between metals and low-dimensional materials, as demonstrated in the case of a 2Dmaterial. Additionally, we extend the proposed approach to account for tunneling currents through the barrier. Finally, we validate our findings with experimental data from a commercial Schottky diode, demonstrating excellent agreement.Wealso discuss non-ideal effects such as image-force lowering
and lateral inhomogeneity of the Schottky barrier. This paper thus proposes an accessible and modern approach to understanding the Schottky diode current–voltage characteristics, making it suitable for both graduate- and postgraduate-level instruction
The Second Quantum Revolution: Unexplored Facts and Latest News
No full textThe Second Quantum Revolution refers to a contemporary wave of advancements and breakthroughs in the field of quantum physics that extends beyond the early developments of Quantum Mechanics that occurred in the 20th century. One crucial aspect of this revolution is the deeper exploration and practical application of quantum entanglement. Entanglement serves as a cornerstone in the ongoing revolution, contributing to quantum computing, communication, fundamental physics experiments, and advanced sensing technologies. Here, we present and discuss some of the recent applications of entanglement, exploring its philosophical implications and non-locality beyond Bell’s theorem, thereby critically examining the foundations of Quantum Mechanics. Additionally, we propose educational activities that introduce high school students to Quantum Mechanics by emphasizing entanglement as an essential concept to understand in order to become informed participants in the Second Quantum Revolution. Furthermore, we present the state-of-art developments of a largely unexplored and promising realization of real qubits, namely the molecular spin qubits. We review the available and suggested device architectures to host and use molecular spins. Moreover, we summarize the experimental findings on solid-state spin qubit devices based on magnetic molecules. Finally, we discuss how the Second Quantum Revolution might significantly transform law enforcement by offering specific examples and methodologies to address the evolving challenges in public safety and security
ReS2/Si 2D/3D vertical heterojunction as a self-powered photodiode
No full text2D/3D van der Waals heterostructures provide an excellent platform for high-performance optoelectronic systems by combining the intrinsic properties of 2D and 3D materials. In this study, we fabricate and study a type II ReS2/Si van der Waals 2D/3D vertical heterojunction with multi-mode photodetection. In the dark, the heterojunction exhibits diode-like behavior with a low reverse current and a high rectification ratio of 103. Under illumination, the device shows a linear response to the light intensity. The ReS2/Si photodetector exhibits stable and repeatable switching behavior and can be operated in self-powered mode with a responsivity of about 0.10mA/W at 10mW incident power and a time response of 300 ls. Based on first-principles calculations, we propose a model to elucidate the photoconduction mechanisms occurring in the ReS2/Si heterostructure
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Single WS2 Nanotube-Based Field Effect Transistor: Ambipolar Conduction and Self-Powered Photodetection
No full textSemiconductive nanotubes offer the potential for miniaturized transistors with enhanced gate control through various configurations. In this work, we fabricated and electrically characterized a single WS2 nanotube-based field effect transistor under both dark and white light illumination at
ambient pressure and temperature. At drain voltages higher than 1 V, the device exhibits ambipolar conduction, with a hole mobility of 0.2 cm2 V-1 s-1 and an electron mobility of 0.13 cm2 V-1 s-1 at Vds = 2 V. The gate modulation has been extensively investigated, applying gate voltages up to 100 V. Furthermore, the WS2 nanotube-based device was evaluated as a
photodetector, demonstrating light-induced modulation of the channel current via both gate and drain control. The single WS2 nanotube-based transistor also operates in self-powered mode, achieving a short-circuit current of 2.6 pA and an open-circuit voltage of approximately 3 mV. The electrical properties of this device show potential for complementary metal-oxide
semiconductor (CMOS) applications, and contribute to the development of optoelectronic devices, including self-powered photodetectors
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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