Stability and electronic structure of stacking faults and polytypes in ZnSnN ₂ , ZnGeN ₂ , and ZnSiN ₂

The formation of stacking faults and polytypes in ZnSnN ₂, ZnGeN ₂, and 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/nm², indicating that the planar defect is expected to be formed in 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.