Novel cladding structure for ZnSe‐based white LEDs with longer lifetime over 10,000 hours

We have demonstrated ZnSe‐based white LEDs with longer lifetime over 10,000 h at 14.5 A/cm2 by introducing an i‐ZnMgBeSe/p‐ZnMgSe double cladding structure, which combined a very thin i‐ZnMgBeSe layer for suppressing electron overflow and p‐ZnMgSSe for efficient p‐type carrier concentration. By adopting the double cladding layer instead of the conventional p‐ZnMgSSe cladding layer, rapid degradation is suppressed. The device simulation and the temperature dependence of optical power showed that the i‐ZnMgBeSe layer played the main role in increasing electron confinement. Our reliability test results indicate that the suppression of the electron overflow is essential to obtain long lifetime acceptable for truly practical use. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)