Full-color displays normally require separate red, green and blue light emitters. A team from the University of Osaka and Ritsumeikan University has demonstrated another approach: a single light-emitting layer that produces several colors when electrically powered at room temperature. The study was published in Applied Physics Letters.

Micro-LED displays promise high brightness, energy efficiency and resolution. However, conventional green and red nitride LEDs can show changes in color as the current increases. Producing several colors also generally requires multiple light-emitting layers or separately manufactured chips, making it difficult to place many pixels into a very small area.

The team used a manufacturing method already widely employed for nitride LEDs to create aluminum gallium nitride LEDs containing terbium ions.