The oxygen dimer in Si: Its relationship to the light-induced degradation of Si solar cells?

It is widely believed that the light induced degradation of crystalline silicon solar cells is due to the formation of a BsO2i recombination center created by the optically excited migration of the oxygen dimer (charge-state-driven motion). In this letter the concentration dependence of the neutral state of O2i on [Oi] in p- and n-type Cz–Si has been determined using infrared absorption. A systematic search for the absorption signature of the dimer in the doubly positively charged state has been unsuccessful. These data strongly suggest that charge-state-driven motion (Bourgoin–Corbett mechanism) of the oxygen dimer cannot occur in typical solar silicon and hence bring into question the accepted degradation mechanism.