Estudos das propriedades optoeletrônicas e mecânicas de nanofitas de h-BN com defeito 558

Abstract

Hexagonal boron nitride h-BN, also known as white graphene, is a material that crystallizes in the form of honeycomb the same as graphene. Because it is an isomorphic material to graphene, it can be found in the formats of nanosheets, nanotubes, nanocones, nanoribbons, among others. With its forms presenting several applications. Consequently, it has the same hybrid to sp2 of graphene, this allows us to infer that there are common properties between the two material types. Like, for example, some mechanical properties. However, in the same way that there are common properties, there are totally different properties between them, for example, optoelectronic properties. Hexagonal boron nitride sheets are insulation materials, their experimental gap energy is worth around 5.9 eV, while zero gap graphene and semimetal. Hexagonal boron nitride h-BN to become a good candidate for use in electronic and optical devices operating in the visible spectrum should reduce its gap energy to ranges between 1,0-3,3 eV. Several techniques can be used to make this decrease occur, for example, the application of electric fields, the use of tensile tension or the inclusion of defects. We have known that during the process of growth of crystalline structures always check for faults, because there is no perfect crystal in the real world. Therefore, it is important to know how these defects influence the properties of the solids and/or crystals. There are several types of defects, so we will study the so called linear defects 558 which are two pentons and an octgon. We’ll investigate the role of the 558-LD defects and the stress tensor in the mechanical, electronic and optic properties of h-BN nanoribbons with zigzag edges. To do this, we have employed first-principle under DFT formalism in Konh-Sham approach to solving the interacting multi-electronic Hamiltonian. For the calculations of optical properties we use the approach of the electrical dipole and for the mechanical properties we have employed the classical theory of elasticity.