Electroluminescence properties of light emitting devices based on silicon nanocrystals

We have fabricated MOS devices where the dielectric layer consists of a substoichiometric SiQ(x) (x < 2) thin film, annealed at 1100degreesC for I h to induce the separation of the Si and SiO2 phases, with the formation of silicon nanocrystals (nc) embedded in the insulating matrix. We have studied the electroluminescence (EL) properties of such devices as a function of the current density and of the temperature. We have evaluated the excitation cross section of Si nc under electrical pumping at room temperature and at low temperature (12 K). Moreover, we have used the experimental EL intensities and decay times to evaluate the radiative rate as a function of the temperature.