Abstract
Metal-oxide-semiconductor structure of ITO/Si-rich SiO2∶Er/Si containing erbium ions and silicon nanocrystals was fabricated by ion implantation of Si and Er combined with post-annealing.The electroluminescence spectra and current-voltage characteristics were measured to investigate the influence of silicon concentration on the excitation mechanism of luminescence centers and conductance process.It was found that the excitation mechanism of erbium ions was variational in the MOS-LED with silicon content.For the silicon concentration less than 5%,the upper levels of erbium can be excited by resonant energy transfer from silicon-oxygen deficiency centers,which induce an enhancement of the 522 nm peak emission intensity of Er3+ ion.For the silicon concentration above 5%,the excess silicon formed silicon nanocrystals by post-annealing.The direct tunneling of electrons between silicon nanocrystals dominate the conductance,resulting a decrease of average energy of hot electrons and quenching of all the electroluminescence peaks of erbium.
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