Local stress distribution in GaN vertical light-emitting diodes fabricated using CLO and LLO methods

We report on the local stress distribution in a GaN-based vertical light-emitting diode (V-LED) fabricated using two types of separation methods: a chemical lift-off (CLO) procedure and a laser lift-off (LLO) technique. The CLO LED exhibits a stronger donor-bound exciton (D0X) emission than the LLO LED, owing to its textured surface morphology and lower amount of damage to the structure. On the basis of the photoluminescence and Raman spectroscopy results, we determine that the CLO GaN LED has an 82 MPa lower residual stress than the LLO GaN LED. Therefore, the CLO technique can be considered as a more effective method to fabricate stress-relieved high-brightness LEDs.This work is supported by the research fund from Hanyang University (20110000000229) and the National Research Foundation of Korea (NRF) grant funded by the Government of Korea (MEST) (201200000002418)