Growth of monolithic full-color GaN-based LED with intermediate carrier blocking layers

Abstract

Specially designed intermediate carrier blocking layers (ICBLs) in multi-active regions of III-nitride LEDs were shown to be effective in controlling the carrier injection distribution across the active regions. In principle, the majority of carriers, both holes and electrons, can be guided into targeted quantum wells and recombine to generate light of specific wavelengths at controlled current-densities. Accordingly we proposed and demonstrated a novel monolithic InGaN-based LED to achieve three primary colors of light from one device at selected current densities. This LED structure, which has three different sets of quantum wells separated with ICBLs for three primary red-green-blue (RGB) colors, was grown by metal-organic chemical vapor deposition (MOCVD). Results show that this LED can emit light ranging from 460 to 650 nm to cover the entire visible spectrum. The emission wavelength starts at 650 nm and then decreases to 460 nm or lower as the injection current increases. In addition to three primary colors, many other colors can be obtained by color mixing techniques. To the best of our knowledge, this is the first demonstration of monolithic full-color LED grown by a simple growth technique without using re-growth process.

Impact of Compositional Nonuniformity in (In,Ga)N -Based Light-Emitting Diodes

“…Indium Gallium Nitride is a successful material for the realization of efficient short-wavelength commercial light emitting diodes (LEDs) [1][2][3]. As a matter of fact, InGaN potentially covers the whole visible spectrum, thus allowing in principle to eliminate the phosphor based down conversion and enabling a color mixing approach, which would allow to further increase overall white LED efficiency [4].…”

III-Nitride Multi-Quantum-Well Light Emitting Structures with Selective Carrier Injection

“…Most natural IBL design applications, however, include structures which essentially require the injection distribution control over MQW active regions with only few QWs, such as monolithic tunable multi-color LEDs. Color control ability of IBL the active region has been demonstrated in the full red-green-blue (RGB) spectrum [11] and recently also used in a white-color LED with a tunable color temperature [13]. Figure 5 presents an example of chromaticity characteristics' control in the three-color IBL LED of the current design.…”

“…The optimal IBL layout would also essentially depend on the required LED operational conditions like nominal bias voltage or injection current. This approach has been successfully applied to achieve the first full-color tunable monolithic LED covering complete RGB gamut [11,12], and recently, has been used to implement a white-color LED with tunable color temperature [13]. In this paper, we demonstrate yet another example of the IBL design of III-nitride MQW LED active region featuring a uniform population of active quantum wells at LED operational voltage.…”

Full-Color Realization of Micro-LED Displays

“…However, because the driving circuit for this structure is too complicated to realize the independent control of each pixel, this technology is currently unable to achieve a full-color micro-LED display, and the IQE and color adjustment range of the device needs to be further optimized. In 2016, Chen’s team inserted a carrier blocking layer (ICBL) between multiple QWs in different active regions [ 107 ]. The experiments showed that ICBL can guide most of the carriers (holes and electrons) into the target QW where they recombine, thereby generating light of a specific wavelength under the injection of different controlled currents.…”