Avaliação do desempenho do transistor MOS sem junções configurado como Nanofio ou FINFET

This work studies how the different gate configurations of junctionless transistors affects their electrical characteristics. Measurements were made on experimental junctionless transistors varying the fin width as well asthree-dimensional numerical simulations, which were calibrated with the experimental results, using the models that best apply to the physics of the junctionless devices. With the three-dimensional simulations adjusted for the fin width, a study was made based on the fin height and its electrical characteristics. These transistors can be configured either as FinFETs or as nanowires depending on the height of the silicon fin. It was obtained that junctionless FinFETs (fin height larger than the fin width), have their best electrical characteristics for long channel devices with narrow fin width and fin height with values greater than 30 nm. For junctionless nanowire transistors (similar fin height and fin width), the best potential can be seen with the decrease in the length of the channel, with narrow width and short height of the silicon fin (around 10 nm). The mobility of the experimental devices analyzed by the Split-CV method, obtaining the effective mobility of the transistors. It was obtained that for a decrease in the fin width it increases the mobility, due to the reduction of Ionized Impurity scattering. Measurements were also made due to the high temperature in triple gate junctionless nanowire transistors to almost planar devices in the range of 300 K to 500 K. It was analyzed by the effective mobility, the effects of the types of carrier scattering depending on the fin width experimentally and via simulations. It has been seen that quasi-planar transistors suffer less from the scattering effect by phonons compared to nanowires, the latter having a greater influence of surface roughness. Comparing the temperature exponents, junctionless transistors suffer more from the effect of scattering by phonons than with Coulomb effect in transistors with narrow fin width. Thus, narrow fin width devices have a greater variation of mobility with temperature compared to quasi-planar devices

Avaliação do desempenho do transistor MOS sem junções configurado como Nanofio ou FINFET

This work studies how the different gate configurations of junctionless transistors affects their electrical characteristics. Measurements were made on experimental junctionless transistors varying the fin width as well asthree-dimensional numerical simulations, which were calibrated with the experimental results, using the models that best apply to the physics of the junctionless devices. With the three-dimensional simulations adjusted for the fin width, a study was made based on the fin height and its electrical characteristics. These transistors can be configured either as FinFETs or as nanowires depending on the height of the silicon fin. It was obtained that junctionless FinFETs (fin height larger than the fin width), have their best electrical characteristics for long channel devices with narrow fin width and fin height with values greater than 30 nm. For junctionless nanowire transistors (similar fin height and fin width), the best potential can be seen with the decrease in the length of the channel, with narrow width and short height of the silicon fin (around 10 nm). The mobility of the experimental devices analyzed by the Split-CV method, obtaining the effective mobility of the transistors. It was obtained that for a decrease in the fin width it increases the mobility, due to the reduction of Ionized Impurity scattering. Measurements were also made due to the high temperature in triple gate junctionless nanowire transistors to almost planar devices in the range of 300 K to 500 K. It was analyzed by the effective mobility, the effects of the types of carrier scattering depending on the fin width experimentally and via simulations. It has been seen that quasi-planar transistors suffer less from the scattering effect by phonons compared to nanowires, the latter having a greater influence of surface roughness. Comparing the temperature exponents, junctionless transistors suffer more from the effect of scattering by phonons than with Coulomb effect in transistors with narrow fin width. Thus, narrow fin width devices have a greater variation of mobility with temperature compared to quasi-planar devices

Coulomb and even-odd effects in cold and super-asymmetric fragmentation for thermal neutron induced fission of 235U

Coulomb and even-odd effects in cold and super-asymmetric fragmentation for thermal neutron induced fission of 235U M. Montoya Instituto Peruano de Energía Nuclear, Canadá 1470, San Borja, Lima, Peru Universidad Nacional de Ingeniería, Av. Túpac Amaru 210, Rímac, Lima, Peru DOI: https://doi.org/10.33017/RevECIPeru2015.0004/ Abstract The Coulomb effects hypothesis is used to interpret even-odd effects of maximum total kinetic energy as a function of mass and charge of fragments from thermal neutron induced fission of 235U. Assuming spherical fragments at scission, the Coulomb interaction energy between fragments ( ) is higher than the -value, the available energy. Therefore at scission the fragments must be deformed, so that the Coulomb interaction energy does not exceed the -value. The fact that the even-odd effects in the maximum total kinetic energy as a function of the charge and mass, respectively, are lower than the even-odd effects of is consistent with the assumption that odd mass fragments are softer than the even-even fragments. Even-odd effects of charge distribution in super asymmetric fragmentation also are interpreted with the Coulomb effect hypothesis. Because the difference between and increases with asymmetry, fragmentations require higher total deformation energy to occur. Higher deformation energy of the fragments implies lower free energy to break pairs of nucleons. This explains why in the asymmetric fragmentation region, the even-odd effects of the distribution of proton number and neutron number increases with asymmetry. Based on a similar reasoning, a prediction of a relatively high even-odd effect in symmetric fragmentations is proposed. Keywords: cold fission, asymmetric fragmentation, symmetric fission, kinetic energy, uranium 235 Resumen La hipótesis del efecto Coulomb es usado para interpretar los efectos par-impar sobre la energía total máxima en función de la masa y carga de los fragmentos de la fisión inducida por neutrones térmicos del 235U. Suponiendo que en la escisión los fragmentos son esféricos, la energía de interacción coulombiana entre fragmentos ( ) es mayor que el valor , la energía disponible. Entonces, los fragmentos en la escisión deben estar deformados, de modo que la energía de interacción coulombiana no exceda el valor de la reacción. El hecho de que los efectos par-impar sobre el valor máximo de la energía cinética total en función de la carga y la masa, respectivamente, son menores que los efectos par-impar de es consistente con la suposición que los fragmentos con masa impar son más blandos que los fragmentos par-par. Los efectos par-impar de la distribución de carga en las fragmentaciones super asimétricas también son interpretados con la hipótesis del efecto Coulomb. Debido a que la diferencia entre y crece con la asimetría, las fragmentaciones requieren mayor energía total de deformación para ocurrir. Mayor energía de deformación de los fragmentos implica menor energía libre para romper pares de nucleones. Esto explica por qué en la region de asimetría, los efectos par-impar en la distribución de número de protons y número de neutrones crece con la asimetría. Basado en un razonamiento similar, se predice un alto efecto par-impar en las fragmentaciones simétricas. Descriptores: fisión fría, fragmentación asimétrica, fisión simétrica, energía cinética, uranio 235.

Some MoS2-based materials for sodium-ion battery

Sodium-ion batteries (SIB) play a promising role in the area of energy storage device researching. MoS2-based materials are considered as one of the most attractive materials for high-performance SIBs owing to their high capacity, high cycle stability and excellent Coulomb effect. This review has summarized the synthesis of MoS2-based materials (MoS2, MoS2/carbon-based materials, MoS2/metal oxides, MoS2/metal sulfides) to emphasize their electrochemical behaviors in SIBs.

Effect of bump structural friction on the performance of bump foil bearing and rotor dynamic behavior: Experimental study

Air foil bearings are a kind of self-acting lubricated bearing, which have potential applications in high-speed turbomachinery. Air foil journal bearings have simple structure that consists of top foil, bump foil, and bearing sleeve, and use gas as working fluid. However, the relative motion of top foil and bump foil, bump foil and bearing sleeve occurs when dynamic pressure is generated as long as there is spinning of shaft. Thus, the friction between each part of bearing should be considered when modeling. Many papers have theoretically shown the effect of Coulomb friction between top foil and top foil, bump foil and bearing sleeve on the static and dynamic performances of air foil journal bearing by developing many bump foil structural models. The results show that this foil structural Coulomb friction can significantly make bump foil stiffer. However, the improvement of the Coulomb friction effect through experiments is quite difficult and there is no study regarding this so far. The purpose of this paper is to certify the Coulomb effect on bearing performance by using experimental method. Two bump foil journal bearings are manufactured with different bearing sleeve surface roughnesses. Foil structure stiffness, bearing lift-off speed, and rotor dynamic behavior supported by two sets of bearings are measured and compared.