POROUS SILICON AND SILOXENE - VIBRATIONAL AND STRUCTURAL-PROPERTIES

Using Raman and infrared transmission spectroscopy, the vibrational pr operties of siloxene (Si6O3H6) and its derivatives are investigated an d interpreted in terms of various structural modifications of siloxene which have been proposed in the past. On the basis of experimental an d theoretical investigations siloxene is found to be a mixture of Si6 rings and/or linear Si chains interconnected by oxygen, and Si planes terminated by H and OH. The influence of thermal annealing, chemical t reatment, and laser irradiation on the structure of siloxene is discus sed in terms of the corresponding changes of the vibrational spectra a nd the x-ray-diffraction patterns. The vibrational properties of silox ene are very similar to those of electrochemically anodized porous Si. Raman, infrared transmission, and photoluminescence measurements of t he two classes of materials are compared and a possible mechanism for the efficient luminescence in porous Si is discussed in light of the s imilarities between siloxene and porous Si.