Increase of blue electroluminescence from Ce-doped SiO_2 layers through sensitization by Gd~(3+) ions

摘要

Efficient blue electroluminescence peak at around 440 nm with a maximum output power density of 34 mW/cm~2 was obtained from Ce and Gd coimplanted metal-oxide-semiconductor light emitting devices. Energy transfer from Gd~(3+) to Ce~(3+) ions was observed during the excitation process, leading to a more than threefold increase of the external quantum efficiency of the blue Ce~(3+) luminescence up to 1.8%. This is evidenced by the increase of the excitation Cross section of Ce~(3+) ions from 4.8 X 10~(-13) to 3.5 X 10~(-12) cm~2 and the simultaneous reduction of the decay time and the impact cross section of Gd~(3+) ions.