Study of electron paramagnetic resonance as a tool to discriminate between boron related defects in barium disilicide

Barium disilicide (BaSi2), composed of Earth-abundant and nontoxic elements, is a promising material for thin-film solar cells. The control of carrier type and carrier concentration by impurity doping is particularly important for the application of BaSi2 to solar cells. However, the presence of defects in semiconductors such as BaSi2 may have a significant impact on the electrical and optical properties of solar cells. In this study, we chose boron to act as a p-type impurity in BaSi2 and studied boron-related defects using the Quantum Espresso method with density functional theory. The formation energy of interstitial boron defects was found to be lower than that of boron in Si vacancy sites. The hyperfine coupling constants of Ba-137 with antisite boron defects (B-Si) are very localized and differ significantly from those of Ba-137 with interstitial boron defects (B-i). This suggests that neutral B-Si and B-i can be identified by electron paramagnetic resonance.

Automated summary

Barium disilicide (BaSi2) is a promising material for thin-film solar cells. In this study, boron was used as a p-type impurity in BaSi2 and its impact on the electrical and optical properties of solar cells was investigated. The results show that interstitial boron defects have lower formation energy compared to boron in Si vacancy sites. Additionally, the hyperfine coupling constants of Ba-137 with different boron defects suggest that they can be identified using electron paramagnetic resonance.