Measurement of the internal quantum efficiency of emission in the local region of the LED chip
A method for measuring the internal quantum efficiency in local areas of the LED chip is presented. The method is based on measuring the emission brightness distribution profiles and 3 dB frequencies of the electroluminescence of the LED at two low values of currents with a digital CMOS camera and calculating the internal quantum efficiency for each image pixel using the formula obtained in accordance with the ABC model of charge carrier recombination
in a heterostructure. The measurement method was tested on the example of commercial blue InGaN LEDs. It is shown that the degree of homogeneity of the internal quantum efficiency distribution profile is significantly higher than the degree of homogeneity of the emission brightness distribution profile, which is due to the inhomogeneity of the distribution of the light extraction efficiency coefficient in different areas of the LED chip. The presented measurement
method can be used to diagnose defects in local areas of the LED heterostructure.