Influence of thermal and laser heating effects on the Raman spectra of luminescent yellow silicon fiber

Luminescent yellow silicon fiber (YSF) is a new form of porous silicon (PS). It was produced by electrochemical etching method by using silicon epitaxial layers of p-type grown on the p+ (111) oriented substrate. Under the excitation of Ar laser, we can observe a strong and broad emission band centered on 650nm at 1.6K. The behaviors of the Raman spectra depend strongly on the laser excitation energy and the temperature of samples. Under certain conditions, the annealing effect occurs and the Raman shift becomes irreversible. The color and transmission spectrum of the fibers are also changed when they are heated from 300 to 1300K. The intensities and the positions of the photoluminescence bands are also changed when the fibers are annealed.