Excited-state Transitions of Self-assembled InAs/InAlGaAs Quantum Dots

We report the structural and optical properties of self-assembled (SA) InAs/InAlGaAs quantum dots (QDs) grown on InP substrates by using molecular-beam epitaxy. When the amount of the arsenic supply and the deposition time were varied, the shape of the SA InAs/InAlGaAs QDs was modified to a relatively round shape, and the QD height was increased from 1.07 to 2.89 nm. From the power and temperature dependences of the PL spectra, the excited-state transitions were confirmed from SA InAs QDs with a material system of InAlGaAs-InP. This is the first observation of clear excited-state transitions for SA InAs/InAlGaAs QDs on InP.