Cascade single-chip phosphor-free white light-emitting diodes

Abstract

In order to resolve the problems existing in the conventional phosphor-converted light-emitting-diodes (LEDs) and red-green-blue LEDs, the cascade single-chip phosphor-free white LED was proposed with GaAsGaN heterojunction direct wafer bonding. Corresponding to the color-matching calculation, the white LED demonstrated the CIE chromaticity coordinates of about (0.3, 0.3) at 20 mA, which was very close to the ideal white light position (13, 13) on the chromaticity diagram. The fabrication and the electrical and optical performances of such white LEDs were described. © 2008 American Institute of Physics.