Sensitization of the blue-green electroluminescence by gadolinium coupled to Si nanocluster embedded in a SiO2 matrix

In this work an enhancement of the blue and green electroluminescence (EL) related to silicon inclusions into SiO2 layer by gadolinium co-doping was investigated. The blue (460 nm) and green (550 nm) EL corresponds to the oxygen-deficient-centres (ODC) and Si nanoclusters with average diameter below 1 nm, respectively. After gadolinium co-doping a fourfold increase of the total EL intensity was observed. It was found that the increase of the blue and green EL is due to the energy transfer from Gd3+ ions to the ODC defects and amorphous silicon nanoclusters. Moreover, the gadolinium co-doping increases the concentration of the small silicon nanoclusters.