Light-emitting diodes of 'warm' white luminescence on the basis of p-n heterostructures of the InGaN/AlGaN/GaN type coated with phosphors made of yttrium-gadolinium garnets

摘要

Electroluminescence spectra and color characteristics of light-emitting diodes of white luminescence based on p-n heterostructures of the InGaN/AlGaN/GaN type with blue emission (λ_(max) ≈ 455 nm) coated with phosphors of the type of aluminum-yttrium-gadolinium garnets activated with the Ce~(3+) ions are studied. The maximum in the excitation spectra of phosphors varies in the range 460-470 nm. The luminescence spectra of phosphors have the peaks from 530 to 590 nm and a width at half-maximum of intensity from 120 to 135 nm depending of the compound composition. The selection of intensities of blue and yellow-orange bands allows one to shift the coordinates of chromaticity of white light-emitting diodes to the region of "warm" luminescence with a correlated color temperature to T _(CC) = 3000 K and maximum luminous efficiency up to 50 lm/W.