9:00 AM - 9:30 AM
[20a-N304-1] [INVITED] Enhancement of Eu luminescence in GaN:Eu via introduction of nanostructures and nanocavities
Keywords:rare-earth-doped semiconductor, nanostructure, nanocavity
Eu-doped GaN (GaN:Eu) has recently emerged as a promising material for red emission on the GaN platform. Luminescence from GaN:Eu is characterized by narrow peaks at ~620 nm from Eu ions owing to the intra-4f transitions, which can be used as red emitting component with a high color purity and a robust wavelength stability. This has never been attained with conventional LEDs utilizing InGaN/GaN-based band-to-band transition. These beneficial luminescence properties are essential for future implementation into next-generation display technologies, including micro-LED displays or augmented-reality devices, where ultra-small LED or laser chips (<10 micron) with three primary colors should be realized on the same GaN platform. We have so far reported the first demonstration of a GaN:Eu-based red LEDs and the luminescence output power has recently exceeded 1 mW at 20 mA by careful optimization of the growth conditions and device designs. We are currently pursuing to further enhance the output power of GaN:Eu-based LEDs.
There are predominantly two approaches to enhance the output power; intrinsic and extrinsic. The former is obtained by controlling the local environment structures of Eu ions in the GaN host such as increase in the Eu concentration. The latter is obtained by manipulating the radiation fields of Eu luminescence. Our previous studies on GaN:Eu indicates that the relatively long radiative lifetime of the Eu ions in GaN:Eu (∼300 µs) is an important factor limiting the output intensity. Therefore, we focus on improving the spontaneous emission rate of Eu ions in the GaN host by introducing nanostructures or nanocavities. In this presentation, we will present our recent progress on the optical/device properties of GaN:Eu-based LEDs with several nanostructure/nanocavities including microdisks and localized surface-plasmon resonance including metal nanoparticles.
There are predominantly two approaches to enhance the output power; intrinsic and extrinsic. The former is obtained by controlling the local environment structures of Eu ions in the GaN host such as increase in the Eu concentration. The latter is obtained by manipulating the radiation fields of Eu luminescence. Our previous studies on GaN:Eu indicates that the relatively long radiative lifetime of the Eu ions in GaN:Eu (∼300 µs) is an important factor limiting the output intensity. Therefore, we focus on improving the spontaneous emission rate of Eu ions in the GaN host by introducing nanostructures or nanocavities. In this presentation, we will present our recent progress on the optical/device properties of GaN:Eu-based LEDs with several nanostructure/nanocavities including microdisks and localized surface-plasmon resonance including metal nanoparticles.