The effect of different barrier layers on gold diffusing into GaN is analyzed by X-ray photoelectron spectroscopy(XPS).By using wafer bonding and laser lift-off(LLO),which uses a KrF excimer laser(248 nm) to separate GaN LED from sapphire substrate,an light emitting diode(LED) GaN epi layer is successfully transferred onto a Si substrate at the temperature of 400 ℃.The surface of samples after laser lift-off(LLO) is observed with microscope and atomic force microscope(AFM).The root-mean-square r...