Infuence of ambient gases on the optical properties of porous silicon layers

Anodically etched silicon in a hydrofluoric acid solution exhibits an efficient room temperature luminescence in the visible region. Origin of this luminescence is still not well understand. Natural explanation is the quantum cinfinement in small silicon crystalities, but surface states due to dangling bonds on the specific furfaces of porous silicon should play an important role in light emission in visible region. The specific surface area of porous silicon filn is very large (~ 200m²/cm³ for samples studied in this work) and sensitive for ambient gases. In this contribution changes of the photoluminenscence spectra of porous silicon samples in the presence of a variety of ambient gases N₂, He₂ and organic vaporous as methanol, acetone are presented.