HOLE-BURNING SPECTROSCOPY OF POROUS SILICON

We report on luminescence hole burning experiments that provide a clue for the mechanism of photoluminescence of porous silicon. A large fra ction of the Light emission is suppressed by an intense resonant pump beam, which introduces an Auger nonradiative recombination. The hole b urnt in the luminescence spectrum has two well-defined onsets related to the TO momentum conserving phonons of Si. At low temperatures the h ole persists for hours. An increase of the temperature heals the spect ral hole, and this is accompanied by a thermoluminescence signal. Thes e results allow us to conclude that most of the luminescence of porous Si arises from radiative recombination between states confined inside the nanocrystals. [S0163-1829(98)00407-X].