Excitation mechanism of Er in Si studied with a free-electron laser

We investigate the influence of infrared illumination using a free-electron laser on the photoluminescence of erbium-implanted silicon material. In ad dition to the earlier reported quenching of the Er-related photoluminescenc e due to dissociation of the intermediate excitation stage, two more featur es of the energy transfer mechanism are revealed. In the wavelength depende nce of the quenching effect a local extreme is detected for a beam energy o f approximately 100 meV. A possible origin of this effect is discussed. Fur ther, the current experiment revealed the presence of non-radiative recombi nation centers which could transfer their energy to Er ions under the influ ence of the infrared beam. The centers were found to be characterized by ex tremely slow generation and decay kinetics. (C) 1999 Elsevier Science B.V. All rights reserved.