The electronic and structural properties of self-interstitial and self-interstitial-related defects in Ge were investigated by first-principles calculations. In accordance with previous works it was found that the split [110] structure was the most stable energetically, among the self-interstitial defects in Ge. However, in disagreement with previous calculations, it was found that the formation energy of the split [110] self-interstitial in Ge was larger than the formation energy of the same defect in Si. The results differed from previous ones because the present calculations converged better with respect to Brillouin zone sampling. Concerning charged defects, it was found that the (+/0) ionization level of the split [110] self-interstitial in Ge was placed at 0.08eV below the valence-band minimum, while the (0/–) level was located at 0.37eV above the valence-band minimum. It was also found that a self-interstitial-related defect, called a fourfold-coordinated defect, was stable in Ge; with a formation energy of 2.82eV.

Electronic and Structural Properties of Germanium Self-Interstitials. M.D.Moreira, R.H.Miwa, P.Venezuela: Physical Review B, 2004, 70[11], 115215