CW InGaN Multiple-Quantum-Well Laser Diodes on Copper Substrates

Continuous-wave (cw) InGaN multiple-quantum-well laser diodes grown on sapphire substrates by metalorganic chemical vapor deposition (MOCVD) were successfully transferred onto copper using an excimer laser lift-off technique. For the laser diodes on copper substrates improved device performance was observed with room-temperature cw threshold currents as low as 68 mA and threshold voltages of 5.9 V. Differential quantum efficiencies of 0.7 W/A were obtained with a laser emission wavelength near 400 nm. GaN-based laser structures transferred onto copper substrates show a significantly reduced thermal resistance resulting in a more than twofold increase in cw output power to more than 100 W. High quality cleaved facets have been obtained for free-standing GaN laser membranes after sapphire substrate removal.