Substitutional Doping Widens Silicene Gap

A numerical study of electronic transport properties of doped silicene is presented. By means of ab initio calculations, a self-consistent scattering potential is derived for boron, nitrogen, aluminum, and phosphorus substitutions in silicene, and the quantum-mechanical Landauer–Büttiker approach is used to evaluate the conductivities of doped silicene ribbons with various impurity concentrations. An individual defect introduces asymmetric electron–hole conductivities that depend on both the type of doping and the position of the foreign atom with respect to the edges. Quantum interference effects at zero temperature are modeled to show that randomly distributed defects over 1 μm long and realistically wide silicon nanoribbons widen the intrinsic electronic gap that arises from quantum confinement. Mobility gaps created at low doping rates may lead to greater efficiency in the design of new silicon-based devices, providing the ability for suitable control of silicon ribbons band gap.