Effects of group-III elements on the growth kinetics of shape-engineered InAs/InAlGaAs quantum dots

We studied the influences of the group-III elements on the shape-engineered InAs/InAlGaAs quantum dots (SEQDs) by photoluminescence (PL) spectroscopy. By alternately depositing a thin InAs layer and a thin InAlGaAs layer on an InAlGaAs buffer layer (so called alternate growth method, AGM), the shape of QDs, especially height, was significantly manipulated. To optically investigate the effect of the introduction of Al and Ga atoms to InAs/InAlGaAs SEQDs (SEQD1), InAs/GaAs (SEQD2) and InAs/AlAs (SEQD3) SEQDs were respectively grown by using the same AGM. The emission peak of the InAs/InAlGaAs SEQDs was 1427 nm with a linewidth broadening of 36 meV at 15 K. The emission peak of the InAs/GaAs SEQDs was red-shifted by 215 nm from the SEQD1 sample. On the other hand, the emission peak for the InAs/AlAs SEQDs was blue-shifted by 111 nm from the SEQD1 sample. From the temperature-dependent PL measurements, the emission peak for the SEQD1, SEQD2, and SEQD3 samples were respectively red-shifted by 18, 5, and 40 nm with increasing temperature. The different behavior in the PL results for the SEQD1, SEQD2, and SEQD3 samples can be attributed to the different atomic distribution of the group-III elements inside the SEQDs.