Effect of adsorption and desorption processes on photoluminescence excitation spectra of porous silicon

Plenty photoluminescence PL. and plenty photoluminescence excitation PLE. spectra, as well as layer structure and surface substances on Si crystallites of porous silicon prepared by different technique, have been investigated by photoluminescence, atomic force microscope AFM.and infrared IR.transmission methods. It is shown that PLE spectra, consisted of several excitation bands, do not depend on Si crystallites sizes. The nature of excitation bands is discussed. q2000 Elsevier Science B.V. All rights reserved