New LED design for next-level virtual reality in immersive displays

From high-flying pterodactyls in games to applying cosmetics before shopping, augmented reality and other immersive technologies are changing the way we play, see, and learn. Low-cost and ultra-emitting diodes (LEDs) that allow a full-color image at high resolution will help immersive displays reach their full potential, but they are not currently available.

Now, in a study recently published in Applied Physics Express, a team led by researchers at Meijo University and King Abdullah University of Science and Technology (KAUST) has successfully developed such LEDs. Their ease of manufacture, with current manufacturing methods, means they can be easily integrated into modern metaverse systems.

Why is the development of improved LEDs necessary for immersive reality? Magnification and realism depend on resolution, detail, and color width. For example, all colors should be visible and different from each other. Gallium indium nitride semiconductors are flexible LED materials that meet all of these requirements.

However, building them as a single unit on the same substrate—rather than as separate entities—is critical to achieving optimal performance. This is what the researchers set out to do.

“We installed in sequence a series of green, green, red LEDs, connected by tunnel channels, based on the quantum principle of electron transport through a thin insulating line – on the same wafer,” explains Motoaki Iwaya, senior author (Meijo) . “We created a complex mesa structure and achieved a pixel density of 330 pixels per inch.”

At a current density of 50 amperes per square centimeter, the wavelengths of the LEDs are 486, 514, and 604 nanometers respectively. The full width at half maximum of the output spectrum is narrow enough to emit red, blue, and green light, and more than enough to distinguish between them.

Senior author Kazuhiro Ohkawa (KAUST) says: “There were fewer wavelengths emitted, and the red and green emissions were much lower than the blue ones—both of which are caused by damage during the fabrication of the device. “Improving crystal growth conditions should improve these defects.”

This work has reduced the usual limitations of previous LEDs based on gallium indium nitride technology. “Preparing devices on low-grade sapphire substrates will be necessary for proper use, and such work is ongoing in our laboratory,” said senior author Daisuke Iida (KAUST). “We believe that our work is an important step towards an immersive visual experience that requires high brightness and definition.”