In this study, we present a high-efficiency InGaN red micro-LED fabricated by the incorporation of superlattice structure, atomic layer deposition passivation, and a distributed Bragg reflector, exhibiting maximum external quantum efficiency of 5.02% with a low efficiency droop corresponding to an injection current density of 112    A / cm 2 . The fast carrier dynamics in the InGaN is characterized by using time-resolved photoluminescence, which is correlated to a high modulation bandwidth of 271 MHz achieved by a 6 × 25-μm-sized micro-LED array with a data transmission rate of 350 Mbit/s at a high injection current density of 2000    A / cm 2 . It holds great promise for full-color micro-displays as well as high-speed visible light communication applications based on monolithic InGaN micro-LED technologies.

The effect of atomic-layer deposition (ALD) sidewall passivation on the enhancement of the electrical and optical efficiency of micro-light-emitting diode (µ-LED) is investigated. Various blue light µ-LED devices (from 5 × 5 µm2 to 100 × 100 µm2) with ALD-Al2O3 sidewall passivation were fabricated and exhibited lower leakage and better external quantum efficiency (EQE) comparing to samples without ALD-Al2O3 sidewall treatment. Furthermore, the EQE values of 5 × 5 and 10 × 10 µm2 devices yielded an enhancement of 73.47% and 66.72% after ALD-Al2O3 sidewall treatments process, and the output power also boosted up 69.3% and 69.9%. The Shockley-Read-Hall recombination coefficient can be extracted by EQE data fitting, and the recombination reduction in the ALD samples can be observed. The extracted surface recombination velocities are 551.3 and 1026 cm/s for ALD and no-ALD samples, respectively.

In this study, high − 3    dB bandwidth yellow-green InGaN/GaN micro-LEDs grown on polar c-plane GaN substrates are realized by using nanoporous distributed Bragg reflectors, which can increase light extraction efficiency and serve as strain-relaxed buffers to mitigate the quantum-confined Stark effect, resulting in improved external quantum efficiency. Moreover, atomic layer deposition technology is introduced for surface defect passivation, thereby reducing the leakage current. As a result, the device exhibits the highest − 3    dB bandwidth up to 442 MHz and a data transmission rate of 800 Mbit/s at a current density of 2.5    kA / cm 2 with on–off keying modulation, and holds great promise for future high-speed visible light communication applications.

The monolithic integration of InGaN-based micro-LEDs is being of interest toward developing full-color micro-displays. However, the color stability in InGaN red micro-LED is an issue that needs to be addressed. In this study, the modified distributed Bragg reflectors (DBRs) were designed to reduce the transmission of undesired spectra. The calculated optical properties of the InGaN red micro-LEDs with conventional and modified DBRs have been analyzed, respectively. The CIE 1931 color space and the encoded 8-bit RGB values are exhibited for the quantitative assessment of color stability. The results suggest the modified DBRs can effectively reduce the color shift, paving the way for developing full-color InGaN-based micro-LED displays.

In this study we demonstrated improved electrical characteristics of Gd 2 O 3 dielectric thin films on n-GaAs substrate by manipulating wet-chemical clean and ͑NH 4 ͒ 2 S passivation. With X-ray photoelectron spectroscopy analysis, the HCl-cleaned GaAs surface was characterized to possess oxide species mainly in the form of As 2 O x near the outmost surface and Ga 2 O x with elemental arsenic close to the interface. These undesirable components could be suppressed through rinsing in NH 4 OH alkaline solution and then performing sulfidization at 80°C, resulting in alleviating the Fermi level pinning effect on Gd 2 O 3 /GaAs capacitor performance. Higher oxide capacitance and alleviated frequency dispersion at the accumulation/depletion regimes were achieved, accompanied by negligible charge trapping ͑Ͻ100 mV͒. Accordingly, gate leakage J g was lowered to ca. 10 −5 A/cm 2 at gate voltage V g = ͑V FB + 1͒ V, which was comparable to the recently reported performance of HfO 2 /GaAs structure with an ultrathin Si/Ge interfacial layer. We attributed the electrical improvements to the enhanced stabilization of high-k/sulfur-terminated GaAs interface due to abatement of native oxides and excess arsenic segregation.