Stability and electronic structure of stacking faults and polytypes in ${\hbox {ZnSnN}_2}$, ${\hbox {ZnGeN}_2}$, and ${\hbox {ZnSiN}_2}$

Abstract

The formation of stacking faults and polytypes in ${\hbox {ZnSnN}_2}$, ${\hbox {ZnGeN}_2}$, and ${\hbox {ZnSiN}_2}$ was investigated by the first-principles density functional theory calculations. To analyze the interactions between the layers of polytypes, we constructed an anisotropic next-nearest neighbor interaction model that reproduced the DFT fitted total energies. Our calculation showed that the stacking fault energy is around 0.28 eV/nm$^2$, indicating that the planar defect is expected to be formed in ${\hbox {ZnSnN}_2}$. The formation of stacking faults can be suppressed by replacing Sn with Si. Stacking faults produce a sawtooth-like potential due to polarization charge, resulting in the separation of electron and hole carriers.