Study of defect density and aging properties of GaN LEDs

As the defects in the LED chip is an important factor affecting the properties of high-power LEDs, a new measurement system is proposed which can get nonradiative recombination defect densities of a LED chip quantification ally, and a new method for evaluation of LED's performance is introduced which based on the relationship model between nonradiative recombination defect and LED's aging property. At the same time, the Current-Voltage characteristics, internal quantum efficiencies and luminescence properties of different LED samples are studied before and after aging tests. The results show that nonradiative recombination defect is the original source for increase of tunneling current, deviation from ideal model of Current-Voltage characteristic and nonlinear phenomena of light-output. From this way, LED chip's lifetime and comparative characteristic could be obtained without prejudice and conveniently.