Effect of Photochemical Oxidization on Stability and SO2 Sensing Performance of Porous Silicon

摘要

The lightly oxidized porous silicon(PS)is prepared by anodizing p-type single crystal silicon and photochemical oxidizing porous silicon.By means of scanning electron microscopy and infrared spectroscopy,both the structure and morphology of PS are analyzed.The sensing performance is evaluated quantitatively by the photoluminescence quenching of PS.The results show that the surface of freshly PS is covered by a lot of rectangle pieces,but its structure is very unstable because the silicon hydride(Si-Hx)on PS surface reacts with the oxygen in the air easily.After oxidized by photochemical method,these rectangle pieces become smaller,its stability is obviously strengthened,and partial Si-Hx band is replaced by Si-O band around 1114cm-1 and OSi-H band around 2249cm-1.The sensing experiment shows that photoluminescence of the lightly oxidized porous silicon is quenched by different concentration of sulfur dioxide reversibly,and the corresponding peak wavelength is not shifted.