Photoluminescence and lasing properties of InAs/GaAs quantum dots grown by metal-organic chemical vapour deposition

Photoluminescence (PL) and lasing properties of InAs/GaAs quantumdots (QDs) with different growth procedures prepared by metalorganicchemical vapour deposition are studied. PL measurements show thatthe low growth rate QD sample has a larger PL intensity and anarrower PL line width than the high growth rate sample. Duringrapid thermal annealing, however, the low growth rate sample shows agreater blueshift of PL peak wavelength. This is caused by thelarger InAs layer thickness which results from the larger 2--3 dimensionaltransition critical layer thickness forthe QDs in the low-growth-rate sample. A growth technique includinggrowth interruption and in-situ annealing, named {indium flushmethod,} is used during the growth of GaAs cap layer, which canflatten the GaAs surface effectively. Though the method results in ablueshift of PL peak wavelength and a broadening of PL line width,it is essential for the fabrication of room temperature working QDlasers.