ON THE ELECTROLUMINESCENCE AND PHOTOLUMINESCENCE OF POROUS SILICON LAYERS SUBMITTED TO ELECTROOXIDATION

Photoluminescent and electroluminescent properties of porous silicon l ayers were studied at different oxidation times after application of a nodic current transients. Changes in the wavelength and intensity of t he emitted photoluminescence could be explained as the consequence of a gradual electrooxidation of silicon structures. Also, the time delay associated with the recording of electroluminescence was interpreted as being due to the oxidation of bulk silicon by holes injected by the power supply. Once bulk silicon becomes oxidized, holes can reach the valence band of silicon microstructures where quantum size effects le ad to visible light emission. (C) 1997 Elsevier Science S.A.