Self-interstitial-hydrogen complexes in silicon

The vibrational properties of interstitial silane (SiH4)(i) and silyl (SiH3 )(i) molecules in crystalline silicon are calculated using a first-principl e, cluster-based, spin-polarized local-density method. The Si-H stretch mod es are found to be redshifted by similar to 300 cm(-1) from those of the is olated molecule, which lie around 2200 cm(-1) These results refute recent s uggestions that modes observed around 2200 cm(-1), and previously assigned to hydrogenated vacancy defects, are due to these interstitial molecules. [ S0163-1829(99)05624-6].