Low-density(~10^(9)cm^(-2)),long-wavelength(more than 1300 nm at room temperature)InAs/GaAs quantum dots(QDs)with only 1.75-mono-layer(ML)InAs deposition were achieved by using a formation-dissolution-regrowth method.Firstly,small high-density InAs QDs were formed at 490℃,then the substrate temperature was ramped up to 530℃,and another 0.2 ML InAs was added.After this process,the density of the InAs QDs became much lower,and their size became much larger.The full width at half maximum of the photoluminescence peak of the low density,long-wavelength InAs QDs was as small as 27.5 meV.
