Influence of wafer quality on chip size-dependent efficiency variation in blue and green micro light-emitting diodes

We propose a key factor associated with both surface recombination velocity and radiative efficiency of an LED to estimate its chip size-dependent radiative efficiencies. The validity of the suggested factor is verified through experimental comparison between various LED wafers. Efficiencies of micro-LEDs from a blue and two green LED wafers are examined by temperature-dependent photoluminescence experiments. Surface recombination velocities are extracted from chip size dependent time-resolved PL results. Possible explanations on the reason why two green wafers show different properties are also given. With the suggested factor, we can provide more accurate prediction on the chip size-dependent efficiency of an LED wafer.

Automated summary

We propose a key factor associated with the surface recombination velocity and radiative efficiency of an LED, which can estimate its chip size-dependent efficiency. We verify the validity of this factor through experimental comparison of different LED wafers. We examine the efficiencies of micro-LEDs from blue and two green LED wafers through temperature-dependent photoluminescence experiments and extract surface recombination velocities from chip size-dependent time-resolved photoluminescence results. We also provide possible explanations for the different properties of the two green wafers. With the suggested factor, we can predict the chip size-dependent efficiency of an LED wafer more accurately.