Development of ZnSe‐based white light emitting diodes with longer lifetimes of over 10,000 hr

Abstract

AbstractWe have demonstrated ZnSe‐based white light emitting diodes (LEDs) with longer lifetimes of over 10,000 hr at 14.5A/cm2 by introducing an i‐ZnMgBeSe/p‐ZnMgSe double cladding structure, which includes a very thin i‐ZnMgBeSe layer for suppressing electron overflow and a p‐ZnMgSSe layer for efficient p‐type carrier concentration. By adopting the double cladding layer instead of only the conventional p‐ZnMgSSe cladding layer, rapid degradation is suppressed and the lifetime tendency becomes similar to that of the LEDs consisting of a III‐V semiconductor system. 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 experimental data and reliability test results indicate that the suppression of the electron overflow is essential to achieve a long lifetime acceptable for practical use. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 154(4): 42–48, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20285