Phosphor-Free GaN-Based Transverse Junction Light Emitting Diodes for the Generation of White Light

We demonstrate a GaN-based phosphor-free near-white-light light-emitting-diode (LED) structure that operates in the visible wavelengths and offers broadening and flattening optical bandwidth performance. The incorporation of GaN-based dual wavelengths (blue and green) multiple-quantum-wells with a transverse p-n junction produces a device which can directly generate stable and near visible white-light emissions. The shape of the optical spectra (440–560 nm) are invariable from low to very high levels of bias currents. The problems of nonuniform carrier distribution and bias dependent electroluminescence spectra that occur in traditional phosphor-free white-light or near-white-light LEDs (with vertical p-n junctions) are eliminated by the demonstrated structure.