In this work, we present the characterization of red InGaN/GaN multiple-quantum-well (MQW) light-emitting diode (LED) structures. The results of photoluminescence (PL) studies show that a thicker n-GaN layer is beneficial for obtaining higher In-content for red MQWs. Our findings imply that in order to achieve high-efficiency InGaN MQWs for red emission, enhancing the uniformity of In-content distribution in the active region and decreasing non-radiative recombination centers are critical challenges.
The pump and probe technique in Raman spectroscopy is used to demonstrate the phonon transport properties of an In0.05Ga0.95N/GaN heterostructure. This method has the advantage of enabling the study of phonon transport processes inside and at interfaces of films with crystal defects by visualizing the shift of phonon-mode energies due to local heating.
We report highly efficient InGaN-based red light-emitting diodes (LEDs) grown on conventional c-plane-patterned sapphire substrates. The packaged LED's external quantum efficiency, light-output power, and forward voltage with a 621 nm peak emission wavelength at 20 mA (10.1 A/cm2) injection current were 4.3%, 1.7 mW, and 2.96 V, respectively. This design development represents a valuable contribution to the next generation of micro-LED displays. This paper has been chosen as an Editor's Pick.
Our Scheduled presentation is selected as “Highlighted talk” at the Spring meeting of the Japanese Society of Applied Physics in Spring 2022. Daisuke Iida et al., “” 23a-E202-10 from 11:45 am March 23 (JPN time) The ratio of the highlighted talks in this conference is usually less than 1%.
The paper reports the investigation of the wet electrochemical etching of n-GaN films in oxalic acid. The results of a number of quantitative physicochemical analysis methods of the products indicated a 6-electron nature of the etching reaction and fully revealed the mechanism of EC oxidation of n-GaN, which includes the formation of intermediates formed by adsorption of the solvent on GaN surface. Clear understanding of this reaction creates a solid foundation for the investigation of transformations of more complicated III-nitride systems for low-damage and high-precision processing of nitride-based devices.
In this research, five sizes (100 × 100, 75 × 75, 50 × 50, 25 × 25, 10 × 10 μm2) of InGaN red micro-light emitting diode (LED) dies are produced using laser-based direct writing and maskless technology. It is observed that with increasing injection current, the smaller the size of the micro-LED, the more obvious the blue shift of the emission wavelength. When the injection current is increased from 0.1 to 1 mA, the emission wavelength of the 10 × 10 μm2 micro-LED is shifted from 617.15 to 576.87 nm. The obvious blue shift is attributed to the stress release and high current density injection.
This talk will provide an overview of the III-nitride-based visible light-emitting diodes (LEDs). Especially, the InGaN-based blue LEDs are very contributed to energy-saving for light sources all over the world.