Color-Tunable Light-Emitting Diodes Based on Rare Earth Doped Gallium Oxide Films
Qixin Guo, Katsuhiko Saito, Tooru Tanaka
Abstract
Color-tunable light-emitting diodes (LEDs) offer a broad spectrum of applications, encompassing augmented and virtual reality displays, indoor lighting, and architectural lighting. Achieving high efficiency and brightness, stable emission, and full-color emission is highly desirable in color-tunable LEDs. However, conventional mass transfer processes have made realizing this technology challenging, because they require extracting red, green, and blue LED chips from different epitaxial wafers. In this spotlight article, we review the progress made toward achieving color-tunable LEDs based on rare earth doped wide bandgap Ga 2 O 3 semiconductors. We have systematically studied the structural and optical characteristics of rare earth (Eu, Er, and Tm) doped Ga 2 O 3 films grown by pulsed laser deposition and observed strong emissions in the red, green, and blue spectral regions from Eu, Er, and Tm doped Ga 2 O 3 films, respectively. We have demonstrated the development of red, green, and blue LEDs based on these Eu, Er, and Tm doped Ga 2 O 3 films and achieved color-tunable LEDs using Eu, Er, and Tm codoped Ga 2 O 3 films. These results demonstrate the great potential of rare earth doped Ga 2 O 3 films for use in color-tunable LED applications.