The influences of laser scanning speed on the structural and optical properties of thin GaN films separated from sapphire substrates by excimer laser lift-off

Abstract

Gallium nitride (GaN) films grown on sapphire substrates were successfully separated and transferred onto silicon (Si) substrates using the laser lift-off (LLO) process induced by an excimer pulsed laser. The structural and optical properties of the GaN films before and after LLO were characterized by x-ray diffraction, atomic force microscopy and Raman spectroscopy. The influences of the laser scanning speed on the structural and optical properties of thin GaN films before and after LLO have been studied, which demonstrated that the laser scanning speed alters the structural quality of the GaN films. The results show that the quality of GaN films is dependent on the LLO process parameter.