Comparison of carrier lifetime for InAs quantum dots in the quaternary barriers on InP substrate

摘要

We have found that the carrier lifetime of an InAs/InGaAsP quantum dot (QD) on an InP substrate is twice that of an InAs/InAlGaAs QD on the same substrate, although the ground-state energy levels and barrier heights of these QDs are comparable. The carrier lifetime of the IrLAs/InAlGaAs QD within the ground state PL band is shorter as the detection wavelength is longer. On the contrary, it shows the same carrier lifetime for the InAs/InGaAsP QD. The difference is interpreted in terms of the smaller conduction band-offset in InAs/InGaAsP QDs compared to InAs/InAlGaAs QDs.