Quick oxidation of porous silicon in presence of pyridine vapor

Abstract

The oxidation of porous silicon (PS) is an important issue to be considered for a better understanding of the physical and chemical properties of this material in view of its possible application in several technological fields (optoelectronics, optical filters, environmental monitoring, etc.). In this work the quick oxidation of mesoporous PS induced by pyridine vapor in air has been studied by infrared spectroscopy. The logarithmic dependences of the oxidation degree, representing the fraction of Si converted into silicon oxide, on the exposure time to pyridine vapor have been measured. Values of this quantity up to 0.9, depending on the PS porosity and on the exposure time, have been obtained. It has been found that the oxidation continues, although at lower rate, even when pyridine treatment is finished. The possible role of pyridine in this chemical oxidation treatment is suggested.