The structural, mechanical and electrical properties of 2D SiC with C-related point defects and substitution of C by foreign atoms

As a wide and direct bandgap semiconductor material, two-dimensional (2D) graphene-like SiC has attracted extensive research attention recently. Native defects and foreign impurities often have remarkable effects on the properties of semiconductors. In this paper, the structural, mechanical and electrical properties of 2D SiC with carbon antisite (CSi), vacancy (VC), interstitial (Ci) and substitution of C by N (NC) and B (BC) have been studied systematically using first-principles calculations. It is found that defects do not cause structural reconstruction for 2D SiC. The formation energies of CSi, VC, NC and BC are not sensitive to the uniaxial strain. CSi and Ci are likely to be formed spontaneously due to the negative formation energy values. In addition, the phonon spectra and elastic constant calculations show that the properties of 2D SiC with VC and Ci are unstable. Furthermore, from the calculations of the band structures and density of states, we observed that the bandgap of 2D SiC is slightly reduced by CSi, VC, Ci, and NC, however is increased by BC. Prominent additional charge states are generated in the bandgap of 2D SiC except for NC. Moreover, the overall carrier mobility of 2D SiC could be significantly reduced by the defects.

Automated summary

This paper systematically studied the effects of defects such as carbon antisite, vacancy, interstitial, and substitution of carbon by nitrogen and boron on the structural, mechanical, and electrical properties of 2D SiC using first-principles calculations. It was found that defects did not cause structural reconstruction for 2D SiC, and carbon antisite and interstitial were likely to be formed spontaneously. The bandgap of 2D SiC was slightly reduced by most defects except for nitrogen substitution, and prominent additional charge states were generated in the bandgap. Moreover, these defects significantly reduced the overall carrier mobility of 2D SiC.