ESTUDIO AB-INITIO DE LAS PROPIEDADES ELECTRÓNICAS DE NANOESTRUCTURAS DE CARBURO DE SILICIO

Abstract

In this work we report the electronic properties of silicon carbide (SiC) nanostructures, specifically, nanowires and nanoporous. It uses the methodology of first principles "Ab-initio” by the theory of density functional by means of density functional theory (DFT). The nanowires and porous SiC nanostructures are modeled by means of the supercell technique, in the case of nanoporous, columns of Si and/or C atoms are removed along the [001] direction of a unit cell with periodic conditions, the dangling bonds of the surface are passivated using hydrogen atoms. In the case of nanowires, also used the supercell model, which uses a unit cell with periodic conditions in one of four chosen directions [001] [110] [111] or [112] as well, are modeled by varying the nanowire width. The surface of the nanowires are saturated with hydrogen atoms in order to clean the states within the energy gap. In the calculation of the electronic properties of nanostructures, the generalized gradient approximation (GGA) exchange-correlation functional used is a revised version of Perdew, Burke and Enzerhof (RPBE), the core electrons are described using ultrasoft and norm-conserving Vanderbilt pseudopotentials. As a result, the study of the electronic properties of SiC nanowires show a decrease in the value of the energy band gap by increasing the diameter of the nanowires, as well as different types of gaps observed according to the growth direction is used . In the case of porous nanostructures, the size of the energy band gap is modified according to the morphology and size of the supercell.