Electroluminescence from Er and Yb co-doped silicon dioxide layers: The excitation mechanism

The excitation mechanism of photo- (PL) and electroluminescence (EL) of erbium ions co-implanted with ytterbium into the SiO2 layer of light emitting MOS devices (MOSLED) was investigated. Ytterbium implanted and annealed samples exhibit the blue and near infrared electroluminescence. The blue electroluminescence at 470 nm appears due to cooperative up-conversion emission in the Yb3+-Yb3+ system, and the near infrared EL at 975 and 1025 nm corresponds to transitions from the multiple state 2F5/2 to the 2F7/2 ground state in the Yb3+ ions. The Er implanted SiO2 exhibits the luminescence in the blue-green and infrared region. The green and blue peaks correspond to radiative transitions from the 2H11/2 or 4S3/2 energy levels and from the 2H9/2 or 4F5/2 energy levels to the 4I15/2 ground state, respectively. We have found that the energy transfer from Yb3+ to Er3+ ions exists only during photoluminescence excitation. The electroluminescence investigation shows the cooperative up-conversion in the Er3+ - Yb3+ system.