First-principles study of interstitial boron and oxygen dimer complex in silicon

摘要

The microstructure of boron (B) and oxygen (O) defect responsible for the light induced degradation (LID) of Czochralski (CZ) silicon solar cells has been investigated for many years.It is newly proposed that the B-O defect could consist of an interstitial boron (Bi) and an oxygen dimer (O2i).In this paper the local density functional theory has been used to investigate the possible configurations of BiO2i complex and their electronic levels.It is found that the most stable configuration of BiO2i complex is constant for all the charge states including neutral,single or double positively charged.This result is obviously not consistent with the assumption of the BiO2i configuration transforming during absorbing an electron in the new model proposed recently.Furthermore,the corresponding electronic level (0/+) is found to be about EC-0.4 eV,close to the measured defect electronic level of LID.