Blue and red electroluminescence of Europium-implanted MOS structures as a probe for the dynamics of microstructure

The strong blue and red electroluminescence from Eu-implanted SiO2 layers were investigated as a function of implantation and annealing conditions. It is shown that the red electroluminescence assigned to Eu3+ ions is favored by low Eu concentrations, low anneal temperatures and short anneal times. Based on a more quantitative analysis of the electroluminescence spectra this preference is explained by a shorter supply of oxygen for higher Eu concentrations and the growth of Europium oxide clusters with increasing anneal temperatures and anneal times. The correlation between electroluminescence and microstructure is supported by transmission electron microscopy investigations and demonstrates that the electroluminescence of Eu-implanted SiO2 layers can serve as a probe for the microstructural development in the active layer of the light emitter.