Electronic Structures of Porous Si Studied by Core-Level Absorption and Photoemission Spectroscopy

For the investigation of the electronic structures of porous Si, 2p core-level absorption and photoemission spectra are measured with synchrotron radiation. The core-level absorption spectra indicate that the conduction band of porous Si shifts toward higher energy as compared with that of bulk Si. This shift correlates well with the photoluminescence blueshift. From photoemission spectra of porous Si in the Si 2p core-level regions, oxidized states on the porous surface are examined.