A comparative study of electroluminescence in rare earth (Er, Yb) doped InP and GaAs light-emitting diodes

The characteristics of the observed electroluminescence from the internal 4f-4f transitions of Er/sup 3+/, at 1.54 mu m, and Yb/sup 3+/, at 1.00 mu m, are reported and compared with an emphasis on the temperature dependence of the emission intensity. In the erbium-doped LEDs the emission at 1.54 mu m shows a gradual decline in intensity with increasing temperature up to about 200 K, followed by a more rapid decline up to room temperature. The total drop in intensity is about a factor of 20 from 77 K to room temperature. This contrasts with the ytterbium-doped LEDs, for which the rare-earth-related intensity drops sharply with temperature above 77 K and is unobservable at room temperature. Such a difference implies a significant difference in the active energy transfer mechanisms for the two rare earth species. On the other hand, the temperature dependence of the intensity in the erbium-doped devices appears to be relatively insensitive to the host material (InP or GaAs). In addition, no significant difference was observed in the peak position of the 1.54- mu m emission between the GaAs devices and that of the InP devices at 77 K and above.<
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