Local order in light emitting porous silicon studied by XEOL and TEY

The local structure of porous silicon has been studied exciting its optical luminescence by X-rays (XEOL). The photoluminescence yield and the total e lectron yield (TEY), recorded simultaneously as a function of the X-ray ene rgy at the Si K edge, give rise to the extended X-ray absorption fine struc tures (EXAFS). Analysis of EXAFS data confirms that the optical luminescenc e of porous Si originates from the nanocrystalline cores and shows that XEO L-EXAFS and TEY-EXAFS are sensitive to different Si local environment. It c an be assumed that XEOL-EXAFS is related only to the light emitting sites w hile TEY-EXAFS is sampling both luminescent and non-luminescent Si sites. ( C) 1999 Elsevier Science B.V. All rights reserved.