  Networks of silicon nanowires possess intriguing electronic properties
surpassing the predictions based on quantum confinement of individual
nanowires. Employing large-scale atomistic pseudopotential computations, as yet
unexplored branched nanostructures are investigated in the subsystem level, as
well as in full assembly. The end product is a simple but versatile expression
for the bandgap and band edge alignments of multiply-crossing Si nanowires for
various diameters, number of crossings, and wire orientations. Further progress
along this line can potentially topple the bottom-up approach for Si nanowire
networks to a top-down design by starting with functionality and leading to an
enabling structure.
