Monolithic multi‐color light‐emitting diodes (LEDs) offer numerous advantages as multi‐functional lighting sources. However, the achievement of full‐color monolithic LEDs spanning from red to blue wavelengths is limited by the InN‐GaN material system. To overcome this limitation, this work demonstrates a new approach using hexagonal epitaxial lateral overgrowth to reduce the density of crystal defects and form micro‐surface structures. By utilizing arrowhead‐like surfaces in semipolar GaN films, indium incorporation can be controlled, leading to larger band‐filling effects and enabling full‐color red, green, and blue emissions from a single LED. Nonetheless, the red emission in monolithic full‐color LEDs is weaker than the blue emission due to the band‐filling induced blueshift that occurs with increasing current injection. To address this issue, pulse amplitude modulation and pulse width modulation modes are introduced to control the emission intensity from red to blue wavelengths. As a result, the study achieves a monolithic trichromatic white LED with color coordinates of (0.2985, 0.3948) and a color temperature of ≈6700 K by simultaneously emitting red, green, and blue LEDs with the same emission intensities. This achievement holds great promise for the development of high‐performance full‐color LEDs for multifunctional lighting sources that can span red, green, and blue wavelengths.
To address the increasing demand for multicolor light-emitting diodes (LEDs), a monolithic multicolor LED with a simple process and high reliability is desirable. In this study, organic–inorganic hybrid LEDs with violet and green wavelengths were fabricated by depositing CsPbBr3 perovskite green quantum dots (QDs) as the light-converting material on InGaN-based violet LEDs. As the injection current was increased, the total electroluminescence (EL) intensities of the hybrid LEDs increased, whereas the light-converted green emission efficiency of the CsPbBr3 QDs decreased. The maximum green-to-violet EL spectral intensity ratio of the hybrid LEDs with CsPbBr3 QDs was achieved with the injection current of <10 mA. Moreover, the EL spectral ratio of the green-to-violet emission decreased at an injection current of 100 mA. The light-conversion intensity of the CsPbBr3 QDs decreased linearly as the junction temperature of the hybrid LEDs was increased with increasing injection current, similar to the temperature-dependent photoluminescence degradation of CsPbBr3 QDs. In addition, the junction temperature of the hybrid LED was minimized by pulse injection to suppress the thermal degradation of QDs and increase the light conversion efficiency to green emission. Therefore, the overall emission spectrum color coordinates of the hybrid LEDs exhibited a red shift from violet to blue in the low-current region and a blue shift toward violet as the green emission of the QDs was decreased above 10 mA.
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