Engineering Nanowire n-MOSFETs at Lg < 8 nm

As metal-oxide-semiconductor field-effect transistors (MOSFET) channel lengths (Lg) are scaled to lengths shorter than Lg<8 nm source-drain tunneling starts to become a major performance limiting factor. In this scenario a heavier transport mass can be used to limit source-drain (S-D) tunneling. Taking InAs and Si as examples, it is shown that different heavier transport masses can be engineered using strain and crystal orientation engineering. Full-band extended device atomistic quantum transport simulations are performed for nanowire MOSFETs at Lg<8 nm in both ballistic and incoherent scattering regimes. In conclusion, a heavier transport mass can indeed be advantageous in improving ON state currents in ultra scaled nanowire MOSFETs.Comment: 6 pages, 7 figures, journa

Full 3D Quantum Transport Simulation of Atomistic Interface Roughness in Silicon Nanowire FETs

The influence of interface roughness scattering (IRS) on the performances of silicon nanowire field-effect transistors (NWFETs) is numerically investigated using a full 3D quantum transport simulator based on the atomistic sp3d5s* tight-binding model. The interface between the silicon and the silicon dioxide layers is generated in a real-space atomistic representation using an experimentally derived autocovariance function (ACVF). The oxide layer is modeled in the virtual crystal approximation (VCA) using fictitious SiO2 atoms. -oriented nanowires with different diameters and randomly generated surface configurations are studied. The experimentally observed ON-current and the threshold voltage is quantitatively captured by the simulation model. The mobility reduction due to IRS is studied through a qualitative comparison of the simulation results with the experimental results

Authentic leadership and job burnout: Mediating effects of positive psychological capitals

This study explored methods for reducing job burnout among organizational members working in highly stressful job environments from the perspective of positive organizational scholarship. In particular, we focused on the role of authentic leadership, an alternative leadership concept that has recently received much attention in the leadership literature. To explain the mechanism underlying the effects of authentic leadership on job burnout, the mediating effect of positive psychological capitals (PsyCap), a critical variable of positive psychology, was analyzed. To examine the proposed hypotheses, data were collected through a survey of employees of the Defense Acquisition Program Administration and analyzed. The results of the analyses demonstrate that authentic leadership has positive effects on team members' positive PsyCap, which in turn reduces their job burnout. In particular, in the relationship between authentic leadership and job burnout, all sub-factors of team members’ positive psychological capital revealed partial mediating effects, with the most significant mediating effect being optimism. Based on the results, we propose several suggestions to strengthen both authentic leadership and positive PsyCap within military organizations

Authentic leadership and job burnout: Mediating effects of positive psychological capitals

This study explored methods for reducing job burnout among organizational members working in highly stressful job environments from the perspective of positive organizational scholarship. In particular, we focused on the role of authentic leadership, an alternative leadership concept that has recently received much attention in the leadership literature. To explain the mechanism underlying the effects of authentic leadership on job burnout, the mediating effect of positive psychological capitals (PsyCap), a critical variable of positive psychology, was analyzed. To examine the proposed hypotheses, data were collected through a survey of employees of the Defense Acquisition Program Administration and analyzed. The results of the analyses demonstrate that authentic leadership has positive effects on team members' positive PsyCap, which in turn reduces their job burnout. In particular, in the relationship between authentic leadership and job burnout, all sub-factors of team members’ positive psychological capital revealed partial mediating effects, with the most significant mediating effect being optimism. Based on the results, we propose several suggestions to strengthen both authentic leadership and positive PsyCap within military organizations

Electron Scattering in Quasi-one-dimensional Nanoscale Transistors

As the sizes of silicon metal-oxide-semiconductor field effect transistors (MOSFET) are scaled down to a nano-meter regime, conventional planar structures are subject to short channel effects. Their subthreshold characteristic is so degraded that a new device structure or material is indispensable to further reduce device dimensions properly. Silicon-on-insulator or double-gate structure is not enough to scale the device dimensions below the channel length of 5 nm. Quasi-one-dimensional structures such as silicon nanowire transistors and graphene nanoribbon transistors may be a solution for ultimate scaling limit. These transistors are numerically explored extensively through atomistic quantum transport simulations based on a tight-binding model. The main focus of this work is to analyze performance metrics of these one dimensional transistors especially when scattering mechanisms such as interface (edge) roughness scattering, electron-phonon scattering, and/or impurity scattering are included. Experimental data are studied and compared with simulation data to provide insights and to explore the device design in ultimate scaling limit. It is found that for high performance logic applications, silicon nanowire transistors show similar performance as graphene nanoribbon transistors. For low power logic applications, graphene nanoribbon tunneling transistors show a great potential in reducing power consumption if cleverly designed

Accelerating a cross-correlation score function to search modifications using a single GPU

Abstract Background A cross-correlation (XCorr) score function is one of the most popular score functions utilized to search peptide identifications in databases, and many computer programs, such as SEQUEST, Comet, and Tide, currently use this score function. Recently, the HiXCorr algorithm was developed to speed up this score function for high-resolution spectra by improving the preprocessing step of the tandem mass spectra. However, despite the development of the HiXCorr algorithm, the score function is still slow because candidate peptides increase when post-translational modifications (PTMs) are considered in the search. Results We used a graphics processing unit (GPU) to develop the accelerating score function derived by combining Tide’s XCorr score function and the HiXCorr algorithm. Our method is 2.7 and 5.8 times faster than the original Tide and Tide-Hi, respectively, for 50 Da precursor tolerance. Our GPU-based method produced identical scores as did the CPU-based Tide and Tide-Hi. Conclusion We propose the accelerating score function to search modifications using a single GPU. The software is available at https://github.com/Tide-for-PTM-search/Tide-for-PTM-search

CO2 reforming of methane for H-2 production in a membrane reactor as CO2 utilization: Computational fluid dynamics studies with a reactor geometry

Computational fluid dynamics (CFD) studies have been carried out for CO2 reforming of methane in both a packed-bed reactor (PBR) and a membrane reactor (MR) with a heating tube as a heat source at the center of a reactor. The effect of a reactor geometry on the temperature and H-2 and CH4 concentration profiles within a PBR and a MR have been investigated numerically by changing the distance of membranes from the center of a heating tube (Dcenter = radial distance between the center of the reactor and the center of the membrane) for a given heating tube temperature. The distances of the center of the membranes in a MR from the reactor center were 0.028 m, 0.03 m, 0.033 m, 0.035 m, 0.038 m, 0.04 m, 0.042 m, 0.044 m and 0.045 m. With the help of COMSOL Multiphysics modeling software, it was possible to visualize temperature and concentration profiles both axially and radially. Interestingly, it was found that H-2 enhancement is proportional to both Dcenter and the magnitude of the H-2 flux. Further studies for the effect of a heating tube radius proposed an optimum radius for a maximum H-2 yield enhancement in a MR. Consequently, it turned out that CFD studies can be used as a critical guideline for an efficient reactor design focusing on a reactor geometry in a MR for given conditions

Engineering Nanowire n-MOSFETs at L-g \u3c 8 nm

As metal-oxide-semiconductor field-effect transistors (MOSFETs) channel lengths (L-g) are scaled to lengths shorter than L-g \u3c 8 nm source-drain tunneling starts to become a major performance limiting factor. In this scenario, a heavier transport mass can be used to limit source-drain (S-D) tunneling. Taking InAs and Si as examples, it is shown that different heavier transport masses can be engineered using strain and crystal-orientation engineering. Full-band extended device atomistic quantum transport simulations are performed for nanowire MOSFETs at L-g \u3c 8 nm in both ballistic and incoherent scattering regimes. In conclusion, a heavier transport mass can indeed be advantageous in improving ON-state currents in ultrascaled nanowire MOSFETs