Positive Bias Temperature Instability Effects in nMOSFETs With $hbox{HfO}_{2}/hbox{TiN}$ Gate Stacks

The Positive Bias Temperature Instability (PBTI) and the stress-induced leakage current (SILC) effects are thoroughly examined in nFETs with $hbox{SiO}_{2}/hbox{HfO}_{2}/hbox{TiN}$ dual-layer gate stacks under a wide range of bias and temperature stress conditions. Experimental evidence of the SILC increase with time is obtained suggesting the activation of a trap generation mechanism. Threshold voltage $(V_{rm T})$ instability is found to be the result of a complicated interplay of two separate mechanisms; filling of preexisting electron traps versus trap generation each one dominating at different stress condition regimes. Furthermore, $V_{rm T}$ instability relaxation experiments, undertaken at judiciously chosen conditions, show that the preexisting and stress-induced traps exhibit similar detrapping kinetics indicating that both types of traps may have similar characteristics. Finally, it is shown that the role of the SILC effect (and the associated trap generation component) on $V_{rm T}$ instability is process dependent and that SILC reduction is accompanied by enhancement of the PBTI device lifetime.      

Channel Hot-Carrier Degradation in Short-Channel Transistors With High- $k$/Metal Gate Stacks

Channel hot-carrier (CHC) degradation in nMOS transistors is studied for different $hbox{SiO}_{2}/hbox{HfSiON}$ dielectric stacks and compared to $hbox{SiO}_{2}$. We show that, independent of the gate dielectric, in short-channel transistors, the substrate current peak (used as a measure for the highest degradation) is at $V_{G} = V_{D}$, whereas for longer channels, the maximum peak is near $V_{G} = V_{D}/hbox{2}$. We demonstrate that this shift in the most damaging CHC condition is not caused by the presence of the high- $k$ layer but by short-channel effects. Furthermore, the CHC lifetime of short-channel transistors was evaluated at the most damaging condition $V_{G} = V_{D}$ , revealing sufficient reliability and even larger operating voltages for the high- $k$ stacks than for the $ hbox{SiO}_{2}$ reference.      

Highly Stable 1.3-$muhbox{m}$ -Wavelength Lasers With p- and n-InP Buried Heterostructure

Highly stable 1.3-$muhbox{m}$-wavelength Fabry–Perot lasers with a p- and n-type InP buried heterostructure have been achieved at an ambient temperature of 85 $^{circ}hbox{C}$. The $t^{0.5}$ deterioration (second-stage degradation) property does not appear clearly within 6000 h, and the saturated first-stage degradation property remains. It is confirmed that the fabricated 1.3-$muhbox{m}$ FP lasers have a different optical-beam-induced-current characteristic from lasers suffering from $t^{0.5}$ deterioration. The first-stage degradation is due to the deterioration of the active layer and is attributed to the fact that some nonradiative recombination centers are generated in the active layer.      

$hbox{NO}_{rm x}$ Aftertreatment Using Thermal Desorption and Nitrogen Nonthermal Plasma Reduction

In this paper, the results of two experiments are reported. First, the performances of various types of nonthermal plasma reactors for $hbox{NO}_{rm x}$ reduction were compared. It was shown that the surface-discharge reactors have as high $ hbox{NO}_{rm x}$ reduction capabilities as pulse-powered wire–cylinder reactors. Second, $hbox{NO}_{rm x}$ treatment using the surface-discharge reactor with a NO-adsorbent zeolite 13X was performed. Thermal desorption was employed for the regeneration of the zeolite. The $hbox{NO}_{rm x}$ of 350 ppm was kept lower than 18 ppm for at least 11 h, whereas it degraded to 75 ppm in the absence of the regeneration. The result suggested the possibility of an aftertreatment system that employed thermal desorption by utilizing the waste heat of diesel engine exhaust and $hbox{NO}_{rm x}$ reduction by using a surface-discharge reactor.      

Time-Dependent Dielectric Breakdown of 4H-SiC/$ hbox{SiO}_{2}$ MOS Capacitors

Time-dependent dielectric breakdown (TDDB) is one of the major issues concerning long-range reliability of dielectric layers in SiC-based high-power devices. Despite the extensive research on TDDB of $hbox{SiO}_{2}$ layers on Si, there is a lack of high-quality statistical TDDB data of $hbox{SiO}_{2}$ layers on SiC. This paper presents comprehensive TDDB data of 4H-SiC capacitors with a $ hbox{SiO}_{2}$ gate insulator collected over a wide range of electric fields and temperatures. The results show that at low fields, the electric field acceleration parameter is between 2.07 and 3.22 cm/MV. At fields higher than 8.5 MV/cm, the electric field acceleration parameter is about 4.6 cm/MV, indicating a different failure mechanism under high electric field stress. Thus, lifetime extrapolation must be based on failure data collected below 8.5 MV/cm. Temperature acceleration follows the Arrhenius model with activation energy of about 1 eV, similar to thick $hbox{SiO}_{2}$ layers on Si. Based on these experimental data, we propose an accurate model for lifetime assessment of 4H-SiC MOS devices considering electric field and temperature acceleration, area, and failure rate percentile scaling. It is also demonstrated that temperatures as high as 365 $^{circ}hbox{C}$ can be used to accelerate TDDB of SiC devices at the wafer level.      

$hbox{1}/f$ Noise Characterization of n- and p-Type Polycrystalline-Silicon Thin-Film Transistors

This paper presents a study of low-frequency-noise properties of n- and p-type polycrystalline-silicon (poly-Si) thin-film transistors (TFTs). The $hbox{1}/f$ noise behavior of these devices prompted the use of the carrier number with correlated mobility fluctuation model for data analysis. From this model, trap densities in this study were found to range from $hbox{3.5} times hbox{10}^{16}$ to $hbox{4} times hbox{10}^{17} hbox{states/eV} cdot hbox{cm}^{3}$, which is indicative of a good top surface of the channel and interface between the oxide and poly-Si. The normalized current noise of the p-channel TFTs changes with the inverse of current, independent of the width $(W)$ -to-length $(L)$ ratio of the channel; the normalized current noise of the n-channel TFTs also changes with the inverse of current, but not independent of the $W/L$ ratio. For smaller currents, noise is caused by traps at or near the oxide/semiconductor interface, whereas for larger currents, the larger contribution to the noise is believed to originate from the bulk.      

PM and $hbox{NO}_{rm x}$ Removal for Diesel Engine Emission Using Ozonizer and Chemical Hybrid Reactor

Over the years, we have investigated particulate matter (PM) and $ hbox{NO}_{rm x}$ reduction using nonthermal plasma-chemical hybrid processes without using catalysts. Among nonthermal plasma hybrid processes, the ozonizer combined with the chemical hybrid reactor was investigated using a 479 cc (5.5 kW) power generation diesel engine. The PM deposited on the diesel particulate filter can be incinerated by ozone and $hbox{NO}_{2}$ in a wide range of flue gas temperature. The NO was oxidized to form $hbox{NO}_{2}$ by ozone, and $hbox{NO}_{2}$ was reduced by the 3% $hbox{Na}_{2}hbox{SO}_{3}$ chemical reactor. As the results, PM deposited on both metal and ceramic filters were successfully removed even at ambient temperature. The rate of PM incineration depends on the amount of ozone injected and was significantly higher than the rate of PM generation. Using 2.4% ozone concentration with a flow rate of 10 L/min, 82% of NO having 720 L/min was oxidized to $hbox{NO}_{2}$, and 78% of $ hbox{NO}_{rm x}$ was removed as a chemical scrubber. However, $ hbox{NO}_{rm x}$ removal was deteriorated about 10% after 1-h operation. This was attributed to $hbox{Na}_{2}hbox{SO}_{3}$ oxidation by air, which was evidenced by the reduction of pH in the chemical reactor.      

Combined Nanoscale and Device-Level Degradation Analysis of $hbox{SiO}_{2}$ Layers of MOS Nonvolatile Memory Devices

In this paper, the impact of an electrical stress applied on MOS structures with a 9.8-nm-thick $hbox{SiO}_{2}$ layer has been investigated at the device level and at the nanoscale with conductive atomic force microscopy (AFM). The goal is to correlate both kinds of measurements when studying the degradation and breakdown (BD) of tunnel oxides of nonvolatile memory devices. In particular, the generation of defects and its impact on leakage current and charge trapping in the tunnel oxide have been analyzed through spectroscopic measurements and current images. The properties and energy of the stress-induced defects (before and after BD) have been roughly estimated by thermally stimulated luminescence and AFM measurements.      

Preparation and Luminescence Properties of Glass Ceramics Precipitated With $hbox{M}_{bf 2}hbox{MgSi}_{bf 2}hbox{O}_{bf 7}{:},hbox{Eu}^{bf 2+}$ (M = Sr, Ca) Phosphor for White Light Source

$hbox{Eu}^{2+}$-doped silicate glasses were prepared in the system $42hbox{SiO}_{2}$– $gamma hbox{CaO}$– $(38gamma)hbox{SrO}$–$20hbox{MgO}$– $0.2hbox{EuO} (gamma = 0, 10, 20, 30, 38)$ by melting under reducing atmosphere. Glass ceramics precipitated with $hbox{M}_{2}hbox{MgSi}_{2}hbox{O}_{7}{:}hbox{Eu}^{2+}$ (M = Sr, Ca) phosphor were obtained by heat-treatment of the glass. They showed broad emission band due to the 5d $rightarrow$ 4f transition of $hbox{Eu}^{2+}$. The peak wavelength shifted from 470 to 530 nm with increasing CaO content. Their emission wavelength can be controlled by changing the compositional ratio of Ca and Sr. Their color coordinates were widely changed from blue to yellowish green region. We have successfully obtained glass ceramic phosphors with excellent durability for a high-power white LED based on near-UV LED.      

Hot-Carrier- and Constant-Voltage-Stress-Induced Low-Frequency Noise in Nitrided High- $k$ Dielectric MOSFETs

Understanding and minimization of low-frequency noise (LFN) originating from high- $k$ (HK) gate dielectrics in newgeneration MOSFETs are of critical importance to applications in RF, analog, and digital circuits. To understand the effect of stress conditions on noise, nMOSFETs were subjected to accelerated hot-carrier stress (HCS) and positive constant-voltage stress (CVS). The additional LFN introduced through stressing was evaluated on nMOSFETs with TiN metal gate and HfSiON gate dielectric. Nitridation of HfSiO gate-dielectric MOSFETs was achieved by either a high-temperature $hbox{NH}_{3}$ anneal or a lower temperature plasma anneal. Influence of different dielectric nitridation procedures on the stress-induced degradation of transconductance, threshold properties, and LFN was studied. Worst degradation conditions, i.e., $V_{g} = V_{d}$, were used for HCS, whereas for CVS, the vertical field was fixed at 10 MV/cm for all transistors to achieve comparable stressing conditions. Plasma-nitrided devices showed less increase in their noise in the linear operation region than the thermally nitrided devices. This difference in noise behavior is attributed to the nitrogen profile across the HK/Si interface and in the bulk of the HK oxide caused by different nitridation techniques. The dielectric defect profile resultant from different annealing techniques was consistent with the spectral form of the observed drain-voltage LFN.      

First-principles investigation on transport properties of $$\hbox {Zn}_{2}\hbox {SnO}_{4}$$ molecular device and response toward $$\hbox {NO}_{2}$$NO2 gas molecules

The transport properties of a \(\hbox {Zn}_{2}\hbox {SnO}_{4}\) device along with adsorption properties of \(\hbox {NO}_{2}\) gas molecules on \(\hbox {Zn}_{2}\hbox {SnO}_{4}\) (ZTO) molecular devices are investigated with density functional theory using the non-equilibrium Green’s function technique. The transmission spectrum and device density of states spectrum confirm the changes in HOMO–LUMO energy level due to transfer of electrons between the ZTO-based material and the \(\hbox {NO}_{2}\) molecules. I–V characteristics demonstrate the variation in the current upon adsorption of \(\hbox {NO}_{2}\) gas molecules on the ZTO device. The findings of the present study clearly suggest that ZTO molecular devices can be used to detect \(\hbox {NO}_{2}\) gas molecules in the trace level.     

High-Power $hbox{Yb}^{{bm 3}{bm +}}$-Doped Phosphate Fiber Amplifier

We report on the development of novel high-power light sources utilizing a $hbox{Yb}^{3+}$-doped phosphate fiber as the gain element. This host presents several key benefits over silica, particularly much higher $hbox{Yb}_{2} hbox{O}_{3}$ concentrations (up to 26 wt%), a 50% weaker stimulated Brillouin scattering (SBS) gain cross section, and the absence of observable photodarkening even at high population inversion. These properties result in a greatly increased SBS threshold compared to silica fibers, and therefore, potentially much higher output powers out of either a multimode large mode area or a single-mode fiber, which means in the latter case a higher beam quality. To quantify these predictions, we show through numerical simulations that double-clad phosphate fibers should produce as much as $sim$700 W of single-frequency output power in a step index, single-mode core. As a step in this direction, we report a short phosphate fiber amplifier doped with 12 wt% $hbox{Yb}_{2} hbox{O}_{3}$ that emits 16 W of single-frequency single-mode output. We also describe a single-mode phosphate fiber laser with a maximum output power of 57 W. The laser slope efficiency is currently limited by the fairly high fiber loss ( $sim$3 dB/m). Measurements indicate that 77% of this loss originates from impurity absorption, and the rest from scattering.      

Structural,electrical and optical properties of $$\hbox {InGaZnO}_{4}$$ and $$\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}$$In29Sn3O48: a first-principles study

First-principles calculations were performed to investigate the electrical and optical properties of \(\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}\) with Sn-doped \(\hbox {In}_{2}\hbox {O}_{3}\) and \(\hbox {InGaZnO}_{4}\) (IGZO). The band structure, density of states, optical properties including dielectric function, loss function, reflectivity and absorption coefficient are calculated. The calculated total energy shows that the most stable crystal structures are type III for \(\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}\) and type II for \(\hbox {InGaZnO}_{4}\). The band structure indicates the both \(\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}\) and \(\hbox {InGaZnO}_{4}\) are direct gap semiconductors. The intrinsic band gap of \(\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}\) is much narrower than that of \(\hbox {InGaZnO}_{4}\), and results in a better electrical conductivity for \(\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}\). The density of states shows the main hybridization occurring between In-4d and O-2p states for \(\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}\) while between In-4d In-5p, Zn-4s and O-2p states for \(\hbox {InGaZnO}_{4}\) near the valence band maximum. The reflectivity index \(R({\omega })\) shows that the peak value of \(\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}\) and \(\hbox {InGaZnO}_{4}\) appears only in the ultraviolet range, indicating that these two materials have all excellent transparency. In addition, the absorption coefficient \({\alpha }({\omega })\) of both \(\hbox {In}_{29}\hbox {Sn}_{3}\hbox {O}_{48}\) and \(\hbox {InGaZnO}_{4}\) is high in the ultraviolet frequency range, and therefore they show, a high UV absorption rate.     

Filament-to-dielectric band alignments in $$\hbox {TiO}_{2}$$ and $$\hbox {HfO}_{2}$$HfO2 resistive RAMs

The next-generation nonvolatile memory storage may well be based on resistive random access memories (RRAMs). \(\hbox {TiO}_{2}\) and \(\hbox {HfO}_{2}\) have been widely used as the resistive switching layer for RRAM devices. However, the electronic properties of the filament-to-dielectric interfaces are still not well understood yet, compared to those of the electrodes and the dielectric. In this work, we study the electronic structures of three typical filament and dielectric structures, \(\hbox {Ti}_{4}\hbox {O}_{7}/\hbox {TiO}_{2}\), \(\hbox {Hf}_{2}\hbox {O}_{3}/\hbox {HfO}_{2}\) and \(\hbox {Hf}/\hbox {HfO}_{2}\), using ab initio calculations. We implement the GGA-1/2 method, which rectifies the band gaps of GGA through self-energy correction. Our calculation predicts an ohmic contact for the \(\hbox {Ti}_{4}\hbox {O}_{7}/\hbox {TiO}_{2}\) interface, where the defective \(\hbox {Ti}_{4}\hbox {O}_{7}\) phase was experimentally identified as the filament composition in \(\hbox {TiO}_{2}\). However, there is a finite Schottky barrier existing in either \(\hbox {Hf}_{2}\hbox {O}_{3}/\hbox {HfO}_{2}\) interface (1.96 eV) or \(\hbox {Hf}/\hbox {HfO}_{2}\) interface (0.61 eV), the two probable filament–dielectric configurations in hafnia-based RRAM. Our results suggest that the distinct filament-to-dielectric band alignments in \(\hbox {TiO}_{x}\) and \(\hbox {HfO}_{x}\) systems account for the much larger resistance window for the latter.     

Analog and RF performance of doping-less tunnel FETs with $$\hbox {Si}_{0.55} \hbox {Ge}_{0.45}$$ source

This paper reports studies of a doping-less tunnel field-effect transistor (TFET) with a \(\hbox {Si}_{0.55} \hbox {Ge}_{0.45}\) source structure aimed at improving the performance of charge-plasma-based doping-less TFETs. The proposed device achieves an improved ON-state current (\(I_{{\mathrm{ON}}} \sim {4.88} \times {10}^{-5}\,{\mathrm{A}}/\upmu {\mathrm{m}}\)), an \(I_\mathrm{ON}/I_\mathrm{OFF}\) ratio of \({6.91} \times {10}^{12}\), an average subthreshold slope (\(\hbox {AV-SS}\)) of \(\sim \) \({64.79}\,{\mathrm{mV/dec}}\), and a point subthreshold slope (SS) of 14.95 mV/dec. This paper compares the analog and radio of frequency (RF) parameters of this device with those of a conventional doping-less TFET (DLTFET), including the transconductance (\(g_{{\mathrm{m}}}\)), transconductance-to-drain-current ratio \((g_\mathrm{m}/I_\mathrm{D})\), output conductance \((g_\mathrm{d})\), intrinsic gain (\(A_{{\mathrm{V}}}\)), early voltage (\(V_{{\mathrm{EA}}}\)), total gate capacitance (\( C_{{\mathrm{gg}}}\)), and unity-gain frequency (\(f_{{\mathrm{T}}}\)). Based on the simulated results, the \(\hbox {Si}_{0.55}\hbox {Ge}_{0.45}\)-source DLTFET is found to offer superior analog as well as RF performance.     

Transport studies of $$\hbox {CeO}_{2}$$ molecular device and adsorption behavior of CO on $$\hbox {CeO}_{2}$$ device: a first-principles investigation

Using density functional theory and the non-equilibrium Green’s function formalism, the transport and CO adsorption properties of \(\hbox {CeO}_{2}\) molecular device are studied. The band structure shows that \(\hbox {CeO}_{2}\) nanostructure exhibits semiconducting nature. The electron density is found to be more in oxygen sites rather than in cerium sites along \(\hbox {CeO}_{2}\) nanostructure. The density of states spectrum shows the variation in density of charge upon adsorption of CO on CeO\(_2\) device. The transmission spectrum provides the insights on the transition of charge in \(\hbox {CeO}_{2}\) molecular device upon adsorption of CO along the scattering region. I–V characteristics confirm the adsorption of CO with the variation of current along \(\hbox {CeO}_{2}\) molecular device. The findings show that \(\hbox {CeO}_{2}\) two probe molecular device can be efficiently used for CO detection in the atmosphere.     

Atomistic tight-binding simulations of quaternary-alloyed $$\hbox {Zn}_{x}\hbox {Cd}_{1-x}\hbox {S}_{y}\hbox {Se}_{1-y}$$ nanocrystals

Advancement of alloyed nanocrystals with attractive structural and optical properties for use in a wide range of physical, chemical, and biological applications represents a growing research field. Employing atomistic tight-binding theory combined with the virtual crystal approximation, the electronic structure and optical properties of quaternary-alloyed \(\hbox {Zn}_{{x}}\hbox {Cd}_{1-{x}} \hbox {S}_{{y}}\hbox {Se}_{1-{y}}\) nanocrystals with experimentally synthesized compositions (x and y) and sizes were investigated. Analysis of the results shows that the physical properties are mainly sensitive to the concentrations (x and y) and the diameter. With decreasing x and y contents, the optical bandgap is reduced because the contributions of the materials with narrower bulk bandgap (ZnSe and CdSe) is mostly promoted. The optical bandgap is reduced with increasing diameter due to the quantum confinement effect. The optical bandgap calculated based on tight-binding calculations shows discrepancy of less than 0.4 eV from experiment. Most importantly, the optical emission is continuously tunable across the entire visible spectrum. The conduction and valence bands are predominantly contributed by cation and anion atoms, respectively. The optical properties are obviously improved in Cd- and Se-rich quaternary \(\hbox {Zn}_{{x}}\hbox {Cd}_{1-{x}} \hbox {S}_{{y}}\hbox {Se}_{1-{y}}\) nanocrystals with large diameter. The atomistic electron–hole interactions can be hybrid-engineered by tuning either the contents (x and y) or diameter. The Stokes shift becomes more pronounced with decreasing alloy concentrations (x and y) and diameter, as described by the trend of the atomistic electron–hole exchange interaction. The present systematic study provides a new avenue to understand the unique size- and composition-dependent structural and optical properties of quaternary-alloyed \(\hbox {Zn}_{{x}}\hbox {Cd}_{1-{x}} \hbox {S}_{{y}}\hbox {Se}_{1-{y}}\) nanocrystals for broad use in multicolor bioimaging, biosensing, light-emitting diodes, solar cells, and other nanodevice applications.     

Numerical analysis of transmission coefficient,LDOS, and DOS in superlattice nanostructures of cubic $$\hbox {Al}_{x}\hbox {Ga}_{1-x}\hbox {N/GaN}$$ resonant tunneling MODFETs

Numerical analysis of the transmission coefficient, local density of states, and density of states in superlattice nanostructures of cubic \(\hbox {Al}_{x}\hbox {Ga}_{1-x}\hbox {N/GaN}\) resonant tunneling modulation-doped field-effect transistors (MODFETs) using \(\hbox {next}{} \mathbf{nano}^{3}\) software and the contact block reduction method is presented. This method is a variant of non-equilibrium Green’s function formalism, which has been integrated into the \(\hbox {next}\mathbf{nano}^{3}\) software package. Using this formalism in order to model any quantum devices and estimate their charge profiles by computing transmission coefficient, local density of states (LDOS) and density of states (DOS). This formalism can also be used to describe the quantum transport limit in ballistic devices very efficiently. In particular, we investigated the influences of the aluminum mole fraction and the thickness and width of the cubic \(\hbox {Al}_{x}\hbox {Ga}_{1-x}\hbox {N}\) on the transmission coefficient. The results of this work show that, for narrow width of 5 nm and low Al mole fraction of \(x = 20\,\%\) of barrier layers, cubic \(\hbox {Al}_{x}\hbox {Ga}_{1-x}\hbox {N/GaN}\) superlattice nanostructures with very high density of states of 407 \(\hbox {eV}^{-1}\) at the resonance energy are preferred to achieve the maximum transmission coefficient. We also calculated the local density of states of superlattice nanostructures of cubic \(\hbox {Al}_{x}\hbox {Ga}_{1-x}\hbox {N/GaN}\) to resolve the apparent contradiction between the structure and manufacturability of new-generation resonant tunneling MODFET devices for terahertz and high-power applications.     

Basic study of a ship navigator's mental workload using salivary NO\documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$_{3}^{-}$ \end{document}

Evaluation of the mental workload during training for ship handling has usually depended on professionals (captain, pilot) who have lots of experience on board. We are attempting to evaluate a ship navigator's mental workload based on a physiological index. The physiological indices, namely heart rate variability (R–R interval), nasal temperature, and salivary amylase, are good indices for reading the mental workload during ship handling. Moreover, we find the possibility of using salivary NO$_{3}^{-}$ as a good index for evaluating the ship navigator's mental workload. Salivary NO$_{3}^{-}$ is expected to have a specific characteristic to represent quick response on the spot and the trend. We confirmed the response of students during simulator training, and then carried out the experiment on professionals on a real ship. We propose that salivary NO$_{3}^{-}$ can show a ship navigator's stress for ship handling in the simulator and on a real ship. This work to evaluate the ship navigator's mental workload using salivary NO$_{3}^{-}$ is the first attempt worldwide. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

First-principle calculations of electronic and ferromagnetic properties of $$\hbox {Al}_{1-x}\hbox {V}_{x}\hbox {Sb}$$

We have used the first-principle calculations of density functional theory within full-potential linearized augmented plane-wave method to investigate the electronic and ferromagnetic properties of \(\hbox {Al}_{1-x}\hbox {V}_{x}\hbox {Sb}\) alloys. The electronic structures of \(\hbox {Al}_{0.25}\hbox {V}_{0.75}\hbox {Sb}, \hbox {Al}_{0.5}\hbox {V}_{0.5}\hbox {Sb}\) and \(\hbox {Al}_{0.75}\hbox {V}_{0.25}\hbox {Sb}\) exhibit a half-metallic ferromagnetic character with spin polarization of 100 %. The total magnetic moment per V atom for each compound is integral Bohr magneton of 2 \(\mu _{\mathrm{B}}\), confirming the half-metallic feature of \(\hbox {Al}_{1-x}\hbox {V}_{x}\hbox {Sb}\). Therefore, these materials are half-metallic ferromagnets useful for possible spintronics applications.