Continuous-wave InGaN laser diodes on copper and diamond substrates

Abstract

InGaN-based optoelectronics were integrated with dissimilar substrate materials using a novel thin-film laser lift-off (LLO) process. The LLO process was employed to integrate InGaN-based laser diodes (LDs) with Cu and diamond substrates. Separation of InGaN-based thin-film devices from their typical sapphire growth substrates was accomplished using a pulsed excimer laser in the ultraviolet regime incident through the transparent substrate. Characterization of the LDs before and after the sapphire substrate removal revealed no measurable degradation in device performance. Reduced threshold currents and increased differential quantum efficiences were measured for LDs on Cu due to a 50% reduction of the thermal impedence. Light output for LDs on Cu was two times greater than comparable LDs on sapphire with a maximum output of 100 mW. Increased light output for LDs on diamond was also measured with a maximum output of 80 mW.