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▲ [14a-A303-3] Size dependence of quantum efficiency of red emission from GaN:Eu for application in micro-LEDs
Keywords:semiconductor, Quantum efficiency, micro LED
When the dimensions of LEDs decrease, problems arise due to smaller feature sizes in terms of the emission efficiency. Due to the relative long free carrier lifetime in GaN quantum wells, the occurrence of non-radiative recombination on the sidewalls of the micro-LED structures increases for smaller devices.
We have demonstrated efficient red LEDs based on Eu-doped GaN. Because the carrier lifetime in Gan:Eu is defined by the trapping of carriers by Eu related traps, it is much shorter in this material. This results in a carrier diffusion length in Gan:Eu LEDs which is much smaller than in conventional quantum well based GaN LEDs, and thus can greatly limit the sidewall related non-radiative recombination in micro-LEDs. We studied the photoluminescence quantum efficiency (QE) of GaN:Eu as function of size and found that the QE did not decrease when decreasing the device size to 10 μm. The high efficiency and lack of decrease hereof for smaller sizes indicates the potential of this material for micro-LED applications.
We have demonstrated efficient red LEDs based on Eu-doped GaN. Because the carrier lifetime in Gan:Eu is defined by the trapping of carriers by Eu related traps, it is much shorter in this material. This results in a carrier diffusion length in Gan:Eu LEDs which is much smaller than in conventional quantum well based GaN LEDs, and thus can greatly limit the sidewall related non-radiative recombination in micro-LEDs. We studied the photoluminescence quantum efficiency (QE) of GaN:Eu as function of size and found that the QE did not decrease when decreasing the device size to 10 μm. The high efficiency and lack of decrease hereof for smaller sizes indicates the potential of this material for micro-LED applications.