Continuous-wave operation of InGaN multiple-quantum-well laser diodes on copper substrates obtained by laser liftoff

The performance characteristics of continuous-wave (CW) InGaN multiple-quantum-well (MQW) laser diodes on copper substrates are reported. InGaN MQW laser diodes (LDs) grown on sapphire substrates by metal-organic chemical vapor deposition were successfully separated from the sapphire and transferred onto copper substrates by using a two-step laser liftoff (LLO) process. Continuous-wave threshold currents as low as 65 mA have been achieved with threshold voltages of 6.5 V with a backside n-contact through the Cu substrate, improved heat dissipation due to the Cu substrate allowed CW laser operation up to a heatsink temperature of 80°C. Significant improvements in light output powers were observed for devices on Cu substrates with maximum CW output power of more than 100 mW