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Blue, green, and red micro‐light‐emitting diodes (LEDs) are expected to serve as light sources for next‐generation full‐color displays. This study fabricates an InGaN LED with an active layer comprising stacked red, green, and blue active layers separated by interlayers using the metal‐organic vapor‐phase epitaxy method for application to a monolithic full‐color LED. Experimental results and band simulations reveal that the emission wavelength during the current injection is controllable via adjustments to the Si doping amount of the interlayer. For a Si doping amount of the interlayer of approximately 2 × 1018 cm−3, only the red active layer closest to the p‐side emits light with a wavelength of ≈610 nm. With a decrease in the Si doping amount in the interlayer, the emission intensity from the n‐side active layer, that is, the green and blue active layers, increases. Moreover, the Si‐doped interlayer acts as a barrier against holes diffusing from the p‐side to the n‐side, thus controlling the amount of carrier injected into each active layer. Additionally, the green and blue active layers under the red active layer improve the emission characteristics of the red active layer. These results indicate the importance of this technology for realizing monolithic, full‐color InGaN‐based LEDs. [ABSTRACT FROM AUTHOR]

The carrier‐transport properties of InGaN red light‐emitting diode (LED) with V‐pits layer and step‐graded GaN barrier are investigated. By using V‐pits layer technology, the inverted pyramid–shaped V‐pit layer forms an energy barrier around the dislocation, inhibits the lateral diffusion of electrons from active layer to the dislocation center, and reduces the probability of non‐radiative recombination rate of electrons and holes. With the increase of the horizontal opening width of the V‐pits layer, the uniformity of holes concentration distribution in InGaN/GaN multiple quantum well (MQWs)‐active region is improved significantly. Compared with the traditional InGaN/GaN MQWs‐active region with fixed well/barrier thickness, step gradient GaN barrier is adopted in the active layer of InGaN red LED, which can reduce the length of the transmission path and improve the injection efficiency of holes into deep quantum wells close to the n‐type region. At injection current density of 200 A cm−2, the internal quantum efficiency of LED D with V‐pits layer and step‐graded GaN barrier is improved by 56.4% as compared with that of reference LED A. In addition, the efficiency droop of LED D can also be effectively alleviated as compared with that of reference LED A. [ABSTRACT FROM AUTHOR]

A novel red LED using Eu‐doped GaN is a promising component for next‐generation micro‐LED displays with small‐size, full‐color, and ultrahigh‐definition. The red LED exhibits narrow‐band red emission and the wavelength is almost independent of ambient temperature and injected current, and the efficiency remains almost constant even at a ultrasmall chip. Monolithic vertically stacked full‐color LEDs on a sapphire substrate is demonstrated. [ABSTRACT FROM AUTHOR]

AlGaInP‐based red light‐emitting diode (LED) arrays are a promising technology. However, due to the difficulty of mesa etching, the small size of red Micro‐LEDs is easily affected by edge effects, resulting in low light output power and difficult to meet the requirements of lighting display. We introduce the fabrication method of flip‐chip red Micro‐LED and exhibit the fabrication of devices with good electrical properties and stable optical properties. [ABSTRACT FROM AUTHOR]

A nitride‐based ultra‐small‐size, full‐color, and high‐resolution micro‐LED display is one of key devices for "a smart society". The ongoing search for an efficient red LED based on GaN is pivotal to the realization of the display. We have worked on the development of semiconductors intracenter photonics. This novel photonics uses the intra‐4f shell transitions of rare‐earth ions doped in semiconductors. In 2009, we invented a narrow‐band red LED using Eu‐doped GaN (GaN:Eu). By continued optimization of the device processing, the output power of the LED is approaching the practical stage. Furthermore, the red LED can be integrated monolithically with conventional blue and green LEDs on the same sapphire substrate. Current status of the GaN:Eu LED and strategies toward further enhancement of its output power using the control of photon fields are reported. [ABSTRACT FROM AUTHOR]