LIGHT-ABSORPTION AND PHOTOLUMINESCENCE OF POROUS SILICON

The results of an experimental study of Raman scattering, photolumines cence, and light absorption and reflection in porous silicon layers ob tained by electrochemical etching of single-crystal wafers are present ed. It is concluded on the basis of an analysis of the experimental da ta that the centers responsible for radiative and nonradiative recombi nation 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 i n the red region of the spectrum. The radiative recombination efficien cy of the latter increases in a thin, near-surface layer of a porous-s ilicon film. (C) 1998 American Institute of Physics.