Optical properties of H terminated Si quantum wires

Abstract

Recent work on Si-based materials, like Si/Ge superlattices, has shown that it is possible to obtain accurate electronic and optical properties using the empirical tight-binding method in the three-center representation. In the present study we extend the method for the case of Si quantum wires and investigate in detail their properties. Si quantum wires are believed to model the physics of porous Si. The interaction of the bulk Si can be transferred to the case of Si quantum wires. In this way we obtain an upshift of the energy band gap for different Si quantum wires, which is in agreement with recent ab initio results. Detailed study of the dielectric function and of the density of states reveals the effects of confinement and the one-dimensional character of the electronic states.