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An accelerated Finite Element Contact Block Reduction (FECBR) approach is presented for computational analysis of ballistic transport in nanoscale electronic devices with arbitrary geometry and unstructured mesh. Finite element formulation is developed for the theoretical CBR/Poisson model. The FECBR approach is accelerated through eigen-pair reduction, lead mode space projection, and component mode synthesis techniques. The accelerated FECBR is applied to perform quantum mechanical ballistic transport analysis of a DG-MOSFET with taper-shaped extensions and a DG-MOSFET with Si/SiO2 interface roughness. The computed electrical transport properties of the devices obtained from the accelerated FECBR approach and associated computational cost as a function of system degrees of freedom are compared with those obtained from the original CBR and direct inversion methods. The performance of the accelerated FECBR in both its accuracy and efficiency is demonstrated.

In this paper, two component mode synthesis (CMS) approaches, namely, the fixed interface CMS approach and the free interface CMS approach, are presented and compared for an efficient solution of 2-D Schrödinger-Poisson equations for quantum-mechanical electrostatic analyses of nanostructures and devices with arbitrary geometries. In the CMS approaches, a nanostructure is divided into a set of substructures or components and the eigenvalues (energy levels) and eigenvectors (wave functions) are computed first for all the substructures. The computed wave functions are then combined with constraint or attachment modes to construct a transformation matrix. By using the transformation matrix, a reduced-order system of the Schrödinger equation is obtained for the entire nanostructure. The global energy levels and wave functions can be obtained with the reduced-order system. Through an iteration procedure between the Schrödinger and Poisson equations, a self-consistent solution for charge concentration and potential profile can be obtained. Numerical calculations show that both CMS approaches can largely reduce the computational cost. The free interface CMS approach can provide significantly more accurate results than the fixed interface CMS approach with the same number of retained wave functions in each component. However, the fixed interface CMS approach is more efficient than the free interface CMS approach when large degrees of freedom are included in the simulation.

Bench-Top Synthesis of Solid-State Copper(I) Sulfides, KCu 7−x S 4 (x = 0.0, 0.12, 0.34), via Nonaqueous Electrochemistry.-Single crystal XRD data for (III) are reported (x = 0.0, space group P4/n, Z = 4; x = 0.12, space group I4/m, Z = 2; x = 0.34, space group I4/m, Z = 2). The temp.-dependent resistivity shows a strong variation with x. Further calorimetry measurements lead to huge Cp anomalies at 292, 186/193, and 208 K corresponding well with the resistivity transitions for related x values. -(HWU, S.-J.; LI, H.; MACKAY, R.; KUO, Y.-K.; SKOVE, M. J.; MAHAPATRO, M.; BUCHER, C. K.; HALLADAY, J. P.; HAYES, M. W.; Chem. Mater. 10 (1998) 1, 6-9; Dep. Chem., Clemson Univ., Clemson, SC 29634, USA; EN)

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