Effect of edge dislocations on structural and electric properties of 4H-SiC

TL;DR

This study uses first-principles density functional theory to analyze how edge dislocations affect the structural and electronic properties of 4H-SiC, revealing their impact on local structure and electrostatic barriers.

Contribution

It provides a detailed first-principles analysis of dislocation effects on 4H-SiC, including creation energies and electronic structure modifications, which was not previously comprehensively studied.

Findings

Dislocation creation energy varies with core distance.

Dislocations induce mid-gap electronic levels.

Electrostatic barriers decrease near dislocation cores.

Abstract

The paper presents a study of two full-core, edge dislocations of opposite Burgers vectors in 4H-SiC, conducted using the first-principles density functional theory methods. We have determined the creation energy of the dislocations as a function of distance between their cores. The radial distribution function has been applied to examine strong impact of the dislocations on the local crystal structure. The analysis of the electronic structure reveals mid-gap levels induced by broken atomic bonds in the dislocation core. The maps of charge distribution and electrostatic potential have been calculated and the significant decrease of the electrostatic barriers in the vicinity of the dislocation cores has been quantified. The obtained results have been discussed in the light of available experimental data.