Optical properties investigation of [nc-Si:SiO 2 /SiO 2 ] 30 periodic multilayer films

The optical properties of 30-layer [nc-Si:SiO2/SiO2]30 periodic films have been studied. The films were prepared by alternately evaporating SiO and SiO2 onto Si(100) substrates, followed by annealing at 1100 ∘C. Spectroscopic ellipsometry spectrum analysis was used to determine the optical constants of the samples via the Forouhi–Bloomer model. The optical bandgap of a single periodic film is calculated. The photoluminescence (PL) spectra of three samples with different thicknesses clearly show that there are two physical origins of the PL process.