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-quan tum-well (MQW) laser diodes on copper substrates are reported. InGaN MQW la ser diodes (LDs) grown on sapphire substrates by metal-organic chemical vap or deposition were successfully separated from the sapphire and transferred onto copper substrates by using a two-step laser liftoff (LLO) process. Co ntinuous-wave threshold currents as low as 65 mA have been achieved with th reshold voltages of 6.5 V with a backside n-contact through the Cu substrat e. Improved heat dissipation due to the Cu substrate allowed CW laser opera tion up to a heatsink temperature of 80 degreesC. Significant improvements in light output powers were observed for devices on Cu substrates with maxi mum CW output power of more than 100 mW.