Theoretical investigation on the electronic states localized at grain boundaries in semiconductors

The electronic states localized at the silicon 〈0 0 1〉{1 3 0} tilt grain boundary were re-investigated by the first-principle calculation based on the density functional theory (DFT) for a starter of the theoretical research on a double Schottky barrier. We found that DFT predicts electrical activity of Hornstra’s model of this grain boundary in contrast with a previous tight binding approximation (TBA) calculation with Chadi’s parameterization predicting electrical inactivity of this grain boundary. It is shown that this disagreement is not brought about by the difference of the most relaxed structures between the TBA and DFT, but is the reflection of the wrong description of the conduction band in the TBA. It follows that previous knowledge on the anti-bonding grain boundary states obtained by TBA need to be verified through more reliable calculations.