On November 28, foreign media reported that researchers at Nagoya University in Japan have developed a method to make LEDs brighter while maintaining their efficiency. This research is expected to reduce LED production costs and environmental impact, while improving their performance in applications such as visible light communication and virtual reality (VR) glasses. The related research results, titled "How to fabricate semi-polar InGaN light-emitting diodes with high internal quantum efficiency: the importance of the internal field," were published in the journal *Laser & Photonics Reviews*.
Image source: Optics.org
Indium gallium nitride (IGaN) LEDs are considered one of the most efficient light sources, but they typically operate only at low power levels. To obtain brighter light, their power needs to be increased. However, adding more power to an LED leads to a decrease in its efficiency, a phenomenon known as efficiency degradation.
One way to overcome the decline in efficiency is to increase the area of the LED, thereby increasing light output, but this also requires the use of larger chips. However, as the chip size increases, the number of LEDs that a wafer can produce will decrease, leading to higher production costs and a greater environmental impact.
To address this, researchers altered the polarization properties of the resulting crystal by tilting the InGaN layer and cutting the wafer in different directions, thereby reducing the decline in LED efficiency. They also fabricated (101̅3) oriented LEDs on an inexpensive sapphire substrate, which exhibited better efficiency at higher power levels.
This discovery provides manufacturers with innovative approaches to developing next-generation LED technologies, such as developing more efficient and brighter Micro LED displays for mobile devices and large-screen TVs; developing LEDs with higher current densities for automotive and specialty industrial lighting applications; and developing LEDs with faster switching speeds for use in visible light communication technologies and VR glasses.
Researchers say that future studies are unlikely to find a better cutting direction, especially on a sapphire substrate.
