ROOM-TEMPERATURE CONTINUOUS-WAVE LASING FROM STACKED INAS GAAS QUANTUM DOTS GROWN BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION/

We report on quantum dot (QD) lasers made of stacked InAs dots grown b y metalorganic chemical vapor deposition. Successful growth of defect- free binary InAs/GaAs QDs with high lateral density (d(l) greater than or equal to 4 x 10(10) cm(-2)) was achieved in a narrow growth parame ter window. The room-temperature photoluminescence (PL) intensity is e nhanced up to a factor of 3 and the PL peak width is reduced by more t han 30% when a thin layer of In0.3Ga0.7As is deposited onto the InAs Q Ds. A QD laser with a single sheet of such InAs/InGaAs/GaAs QDs exhibi ts threshold current densities as low as 12.7 and 181 A/cm(2) at 100 a nd 300 K, respectively. Lasers with threefold stacked QDs show ground- state lasing and allow for cw operation at room temperature. (C) 1997 American Institute of Physics.