Electronic and structural properties of silicon carbide nanowires

We present density-functional calculations of the geometrical and electronic structure of nanometer-thick silicon carbide nanowires grown along the < 100 > axis. We discuss first hydrogen-passivated wires and show that the quantum confinement results in a broadening of the band gap. Second, we study pure nanowires. In this case the facets' dangling bonds strongly reconstruct and the surface states that form turn the system into metallic. Both the gap broadening and the surface reconstruction driven metalization are analyzed in the case of C- and Si-rich wires.