Electroluminescence spectra study of Au/Si/SiO2 superlattice/p-Si structures with gamma irradiation

Visible light emission can be observed from alternation-magnetron-sputtered Si/SiO2 superlattices (SSOSLs) when the forward bias exceeds 5 V. The electroluminescence (EL) spectra of Au/ amorphous Si/SiO2 superlattice/p-Si structures with Si layers of nine different thicknesses showed a peak located at 650 nm. After the SSOSLs were irradiated by a Co-60 radiative source, a new strong 470 nm blue peak emerged from the EL spectra in all the Au/ Si/SiO2 superlattice/p-Si structures. We rule out the possibility that both the excitation and recombination processes of the observed EL are from the nanometre silicon layers, as described by the quantum confinement model. The experimental results can be explained by electrons from the Au electrode and holes from the p-Si substrate tunnelling into the luminescence centres in the SiO2 layers and recombining radiatively there. Copyright (C) 2001 John Wiley & Sons, Ltd.Chemistry, PhysicalSCI(E)CPCI-S(ISTP)