Analysis of degradation of GaN-Based light-emitting diodes

This paper analyzes the degradation of the electrical, optical and thermal characteristics of the light-emitting diodes (LEDs). Two types of LEDs which are defined as sample A and sample B are tested. Their electrical, optical and thermal characteristics have been continuously monitored during the test. The results of our analysis demonstrate that ohmic contacts and resistivity of bulk are stable over stress time; the die attach materials of sample B get worse, but the active layer is better than sample A; the depletion region of sample A is getting worse and sample B is stable. The analysis above offers a new method to find which part degrades seriously.