Light absorption and photoluminescence of porous silicon

The results of an experimental study of Raman scattering, photoluminescence, and light absorption and reflection in porous silicon layers obtained by electrochemical etching of single-crystal wafers are presented. It is concluded on the basis of an analysis of the experimental data that the centers responsible for radiative and nonradiative recombination in this material are of a multiple character. The experimental data show that the centers whose maximum of optical excitation lies in the blue-green region of the spectrum have a uniform distribution, in contrast with the centers whose region of efficient excitation lies in the red region of the spectrum. The radiative recombination efficiency of the latter increases in a thin, near-surface layer of a porous-silicon film. Fiz. Tekh. Poluprovodn. 32, 1001–1005 (August 1998)