Ab initiostudy of substitutional boron and the boron-hydrogen complex in diamond

Abstract

Local-density-functional theory is used to determine the structure of minimum energy of a substitutional boron atom in diamond and a hydrogen atom bonded to that point defect. It is found that the substitutional boron is an on-site impurity with a vibrational frequency of 1228 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$. It is also found that the hydrogen atom takes up a position in a 〈100〉 direction relative to the boron atom. This is in contrast to the structure of similar acceptor-hydrogen complexes in silicon and other tetrahedrally bonded semiconductors. The vibrational frequency associated with the stretching mode of the boron-hydrogen bond is calculated to be between 2540 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ and 2655 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$.