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Coaxial semipolar InGaN/GaN microwire array LED with substantially suppressed efficiency droop
摘要： GaN nano/micro-structure based light-emitting diodes (LEDs) have drawn much attention owing to their potential applications in display and optoelectronics integration. Here, we have fabricated coaxial semipolar InGaN/GaN multiple quantum wells (MQWs) microwire array LED with superior performances in suppressing efficiency droop. The results show that our as-synthesized microwire has two semipolar planes (1 01), and the InGaN/GaN MQWs have superior crystal quality. In addition, the efficiency droop ratio of our device is about 9.7% as the injected current increases from 3 to 100 A/cm2, which is largely declined by 47% compared with that of the conventional polar c-plane LEDs. Meanwhile, the microwire array LED reveals a small wavelength shift (3nm) as the injected current increases from 3 to 23 A/cm2. The effective advances in the device should be attributed to the weaker quantum-confined stark effect of InGaN/GaN MQWs in semipolar plane. This work proposes a high repeatability method to fabricate microwire array LED for future optoelectronic integrated systems.
关键词： LED,Quantum-confined stark effect,Semipolar,GaN microwire array,Efficiency droop
更新于2025-09-16 10:30:52
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Polarized monolithic white semipolar (20–21) InGaN light-emitting diodes grown on high quality (20–21) GaN/sapphire templates and its application to visible light communication
摘要： We demonstrate efficient, polarized and monolithic white semipolar (20–21) InGaN light-emitting diodes (LEDs) grown on high crystal quality 4-inch (20–21) GaN/sapphire template. Materials growth by metal-organic chemical vapor deposition (MOCVD) and characterization by atom probe tomography (APT) were carried out. The fabricated regular 0.1 mm2 size LEDs show a high electrical performance with an output power of 3.9 mW at 100 mA, an emission spectrum with two peaks located at 445 nm and 565 nm, a CIE point of (0.37, 0.42) and a polarization ratio of 0.30, which make them promising candidates for backlighting in liquid crystal displays (LCDs) application. Moreover, the fabricated square phosphor-free white μLED with size ranging from 20 to 60 μm, exhibit a high 3 dB modulation bandwidth of 660 MHz in the visible light communication (VLC) system, which benefits from the shorter carrier lifetime grown on the semipolar (20–21) plane. To our best knowledge, this is the first demonstration of monolithic white semipolar μLEDs in the VLC application, which can overcome the limitation of the slow frequency response of yellow phosphors converted commercial white LEDs. These results demonstrate the huge potentials to produce high efficiency monolithic white semipolar InGaN LEDs on cost-effective large area sapphire substrates.
关键词： Polarization,Light-emitting diodes,Atom probe tomography,Semipolar GaN,Visible light communication
更新于2025-09-12 10:27:22
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Asymmetry of the Defect Structure of Semipolar GaN Grown on Si(001)
摘要： The defect structure of a thick (~15 μ m) semipolar gallium nitride (GaN) layer grown by hydride–chloride vapor phase epitaxy on a Si(001) substrate with buffer layers has been studied by transmission electron microscopy. The asymmetry of the defect structure of GaN epilayer has been revealed and analyzed. The influence of this asymmetry on the rate of decrease in the density of threading dislocations in the growing epitaxial layer is discussed.
关键词： transmission electron microscopy,semipolar GaN,threading dislocations,hydride–chloride vapor phase epitaxy,defect structure
更新于2025-09-04 15:30:14