LOW-THRESHOLD CONTINUOUS-WAVE ROOM-TEMPERATURE OPERATION OF ALXGA1-XAS/GAAS SINGLE QUANTUM-WELL LASERS GROWN BY METALORGANIC CHEMICAL VAPOR-DEPOSITION ON SI SUBSTRATES WITH SIO2 BACK COATING

We demonstrate the first room-temperature low-threshold continuous-wave (cw) operation of Al0.3Ga0.7As/GaAs single quantum well (SQW) heterostructure lasers grown by metalorganic chemical vapor deposition (MOCVD) on Si substrates using techniques of SiO2 back coating and thermal cycle annealing. The all-MOCVD-grown SQW lasers on GaAs/Si with etch pit density of 1.5× 107 cm-2 have threshold current as low as 55 mA (1.41 kA/cm2) under cw at room temperature. The SiO 2 back coating is effective to obtain excellent current-voltage characteristics. Thermal cycle annealing is also found to improve the crystallinity of GaAs/Si and to contribute to room-temperature cw operation of the lasers on Si substrates.