Electroluminescence properties of SiOx layers implanted with rare earth ions

In this work we have studied the structural, electrical and optical properties of MOS devices, where the dielectric layer consists of a SiOx (x < 2) thin film prepared by plasma enhanced chemical vapor deposition and implanted with rare earth ions. As deposited SiOx films were annealed at high temperature (> 1000 degreesC) to induce the separation of the Si and SiO2 phases with the formation of Si nanocrystals embedded in the insulating matrix. Devices based on this system present a strong light emission at room temperature at a wavelength of about 900 nm. Devices emitting at different wavelengths have been fabricated by implanting SiOx films with Er or Tin. Devices based on Er-doped Si nanoclusters film exhibit an intense 1.54 mum room temperature electroluminescence (EL). We have calculated the excitation cross-section for Er ions in presence of Si nanoclusters under electrical pumping and the value is similar to1 x 10(-14) cm(2), comparable to the value found for the electrical excitation of undoped Si nanocrystals. Finally, devices based on Tm-doped Si nanoclusters exhibit two EL peaks at 0.78 and 1.7 mum.