Color-Tunable Light-Emitting Diodes Based on Rare Earth Doped Gallium Oxide Films

Color-tunable light-emitting diodes (LEDs) offer a broadspectrumof applications, encompassing augmented and virtual reality displays,indoor lighting, and architectural lighting. Achieving high efficiencyand brightness, stable emission, and full-color emission is highlydesirable in color-tunable LEDs. However, conventional mass transferprocesses have made realizing this technology challenging, becausethey require extracting red, green, and blue LED chips from differentepitaxial wafers. In this spotlight article, we review the progressmade toward achieving color-tunable LEDs based on rare earth dopedwide bandgap Ga2O3 semiconductors. We have systematicallystudied the structural and optical characteristics of rare earth (Eu,Er, and Tm) doped Ga2O3 films grown by pulsedlaser deposition and observed strong emissions in the red, green,and blue spectral regions from Eu, Er, and Tm doped Ga2O3 films, respectively. We have demonstrated the developmentof red, green, and blue LEDs based on these Eu, Er, and Tm doped Ga2O3 films and achieved color-tunable LEDs usingEu, Er, and Tm codoped Ga2O3 films. These resultsdemonstrate the great potential of rare earth doped Ga2O3 films for use in color-tunable LED applications.