Light emitting capacitors (LECs) were fabricated using silicon rich oxide (SRO) films as active layer. Blue and red electroluminescence (EL) was observed by changing the silicon nanoparticle (Si-np) size from 1.5 to 2.7 nm embedded in the silica matrix. EL is ascribed to the charge injection into the Si-nps embedded in the SRO films through a balanced transport network. The EL emission is observed with the naked eye and in daylight conditions on the whole area of devices. Therefore, these results prove the feasibility to obtain LECs by using simple capacitors with SRO films as the active layer.

Silicon rich oxide (SRO) is a silicon compatible material that could solve the light emission limitation inherent to bulk silicon. However, not many applications are yet reported, since still much research has to be done. In this paper, SRO superficial films were obtained by low pressure chemical vapor deposition. Structural and optical characterization was done by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy (FTIR) corroborating that after annealing, the SiO and the Si 2 O phase clearly increases. Emission of SRO in the range between ultra violet and near-infrared is determined by photo, electro and cathode luminescence. Assuming that emission is due to agglomerates of Si-O compounds, computational simulations of cyclic chains of SiO were done to calculate the FTIR spectra, emission and HOMO-LUMO densities. It was found that emission of molecules with less than 10 silicon atoms is not likely to be present in the annealed films. However, for molecules with more than 13 silicon atoms, the emission extends to the visible and near infrared region. The calculated FTIR agrees with the experimental results.

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