Auger effect as the origin of the fast-luminescent band of freshly anodized porous silicon

Time-resolved photoluminescence measurements are performed on oxidized and fresh porous silicon at room temperature. Comparing the evolution of the nanosecond time-delayed photoluminescence (PL) in both cases, a new feature of the PL spectra is identified: a fast red band, present both in fresh and aged samples. The nonlinear excitation intensity dependence of this component is described by a simple model, where the Auger effect inside isolated silicon quantum dots plays the dominant role.