Effects of thin GaAs cap layer on optical properties of InAs/InGaAs/InP quantum dot

We have studied the influence of thin GaAs capping layer (5-10 monolayers) on optical properties of InAs QDs. After the growth of thin GaAs capping layer, the 70 nm thick top InGaAs capping layer was deposited at 570 /sup o/C or 610 /sup o/C. The insertion of thin GaAs cap layer on QDs led to blue shift of peak of photoluminescence (PL). In addition, full width at half maximum (FWHM) of the PL peak decreases from 35 mev to 20 mev by inserting 10 ML GaAs layer.