Effect of the desorption process on photoluminescence excitation spectra of porous silicon

Photoluminescence (PL), photoluminescence excitation (PLE), and FTIR methods were used to study the PL excitation mechanism in porous silicon (PS). Two types of PLE spectra were observed, consisting of two (visible and ultraviolet) and one (only ultraviolet) bands. The intensities of each PLE band depend differently on the anodization conditions during aging and thermal treatment. Two excitation channels were shown to exist in PS. The visible PLE band at 300 K was attributed to light absorption of some species on the surface of Si wires. (Author)