1,720,967 research outputs found
Electron transport properties of diarylethene photoswitches by a simplified NEGF-DFT approach
No full textA homemade program called FOXY has been used for the theoretical investigation on the conducting properties of two diarylethene based molecules, which, according to recent literature data, can act as photoswitches. FOXY uses a simplified method relying on NEGF theory coupled to DFT calculations and using a suitable electric field to mimic the bias voltage, together with a simple representation of the electrodes. The results confirm the experimental findings and are rationalized by analyzing the space extension of the pertinent molecular orbitals in the ON and OFF electronic states and confirm the FOXY program as a cheap and reliable code to be used in the field of molecular electronics
Design guidelines for GaSb/InAs TFET exploiting strain and device size
No full textA simulation study exploring the possibility of performance improvements for GaSb/InAs nanowire TFETs under appropriate stress conditions is carried out. It is demonstrated that biaxial tensile strain induces a remarkable enhancement of the on-state current thanks to bandgap reduction; however, a degradation of the ambipolar behavior is observed as well. Some stress intensity values and device geometry configurations are investigated. The best simulated device can achieve an on/off current ratio of about 3×107 with ION≈0.33 mA/μm at VDD=0.3 V
Impact of Strain on Tunneling Current and Threshold Voltage in III-V Nanowire TFETs
Full text linkA simulation study on the effects of different strain configurations on n-type III-V-based nanowire tunnel-FETs is presented, with the aim to determine optimal strain conditions to enhance device performance. We find that both the biaxial tensile and the uniaxial compressive stress shift up the valence band. Biaxial stress, however, lowers the conduction band as well, thus providing the largest reduction of the energy bandgap. Instead, the gap variation is limited for the biaxial compressive and uniaxial tensile strains. Moreover, for these strain conditions, the lowest conduction subband is not connected to the highest valence subband via the imaginary wave vector but to a lower one. This leads to an effective bandgap higher than the expected, which reflects into a large threshold increase and a degradation of the ON-state current
Impact of Traps and Strain on Optimized n- and p-Type TFETs Integrated on the Same InAs/AlGaSb Technology Platform
No full textA simulation study on the impact of interface traps and strain on the I - V characteristics of co-optimized p- and n-type tunnel FETs (TFETs) realized on the same InAs/Al0.05Ga0.95Sb technology platform is carried out, using a full-quantum ballistic simulator. In order to capture the effect of interface/border traps on the device electrostatics consistently with carrier degeneracy and ballistic transport, the classical Shockley-Read-Hall theory has been properly generalized. The effect of an experimental Dit distribution of a high-k gate stacks on InAs has been investigated. Unfortunately, traps induce a significant reduction of the ON-state current. However, it turns out that localized strain at the source/channel heterojunction caused by lattice mismatch is able to induce for the n-type TFET, a performance enhancement with respect to the ideal device even in the presence of traps. On the contrary, for the p-type one, a current degradation â 18 % is observed
A full-quantum simulation study of InGaAs NW MOSFETs including interface traps
No full textThe interaction between strain and border traps in short-channel InGaAs NW MOSFETs is investigated through full-quantum 3D simulations based on a k·p Hamiltonian. Traps induce a sizable degradation of the ON-current, which can be recovered through the application of a suitable strain, provided the quantization effects, which increase by scaling the NW lateral size, do not become too large
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
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
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