QUANTUM-CHEMICAL STUDY OF 2D ALLOTROPES OF SILICON CARBIDE

Abstract

Multilayer structures based on SiC are considered to be among the most promising materials of nanoelectronics, since they have a non-zero bandgap width up to 3.72 eV and can be used to produce heterostructures.The aim of the paper is to establish the dependency between the rearrangement of the electronic structure of 2D allotropes of silicon carbide and a successive change in the number and confi guration of layers. The material of the study were single-layer silicon carbide and 6 allotropic modifi cations of SiC with the number of layers n = 2, 3. Quantum-chemical modelling of the electronic structure of 2D allotropes of silicon carbide was performed using the density functional theory (DFT) in the local spin density approximation (LSDA). It was established that multilayer structures of silicon carbide form a family of semiconductor materials with a bandgap width from 1.132 to 2.150 eV, whose properties are determined by the number and confi guration of layers. It was also established that two- and three-layer 2D silicon carbide with thepackaging type AAA is the most stable among the analysed allotropic modifi cations and has a maximum band gap of 2.150 and 1.568 eV. It was found that layer-by-layer growth of structures determines a change in the type of the semiconductor from a direct bandgap single-layer SiC to an indirect bandgap with the number of layers n=2, 3. An exception is the metastable ABA structure with a direct bandgap of 1.339 and 1.132 eV (n = 2, 3). Since this allotropic modifi cation has a structure similar to the structure of multigraphene, it can be stabilized in iC/multigrapheneheterostructures.

Keywords

• SiC
• 2D allotropes
• quantum-chemical simulation
• electronic structure.