Origin of the 370-nm luminescence in Si oxide nanostructures

The nature of the ∼370-nm (3.35-eV) photoluminescence (PL) in Si oxide and nanostructures, which has a PL excitation band at ∼260nm, is studied experimentally and theoretically. It is revealed that the PL occurs at the interface between Si structure and its oxide and is closely associated with a characteristic infrared absorption band at ∼1250cm−1. Spectral analyses suggest that the ∼370-nm PL originates in the –SiO3 group, which bonds to Si structural surface. The density functional theory calculations are consistent with our experiments. This work clarifies some controversies regarding the ∼370-nm PL mechanisms in a number of Si oxide and nanostructures.