Indium-doped silicon for solar cells - light-induced degradation and deep-level traps

Indium-doped silicon is considered a possible p-type material for solar cells to avoid light-induced degradation (LID), which occurs in cells made from boron-doped Czochralski (Cz) silicon. Herein, the defect reactions associated with indium-related LID are examined and a deep donor is detected, which is attributed to a negative-U defect believed to be In${}_s$O${}_2$. In the presence of minority carriers or above bandgap light, the deep donor transforms to a shallow acceptor. An analogous transformation in boron-doped material is related to the B${}_s$O${}_2$ defect that is a precursor of the center responsible for BO LID. The electronic properties of In${}_s$O${}_2$ are determined and compared to those of the B${}_s$O${}_2$ defect. Structures of the B${}_s$O${}_2$ and In${}_s$O${}_2$ defects in different charges states are found using first-principles modeling. The results of the modeling can explain both the similarities and the differences between the B${}_s$O${}_2$ and In${}_s$O${}_2$ properties. (© 2021 The Authors. physica status solidi (a) applications and materials science published by Wiley‐VCH GmbH)