In this work we investigated the electronic states of InAsP/GaAs QDs using photoluminescence (PL) and photomodulated transmission (PT) experiments. PL measurements were performed as a function of temperature and excitation power. As the recombination energy of the InAsP/GaAs QDs resides in between the extremes InAs/GaAs and InP/GaAs QDs, these two materials were also analyzed. From PL experiments we could identify the recombination from the QDs ground state and the contribution of the InAsP and InP wetting layer (WL) with a macro PL technique. PL measurements of annealed samples allowed us to to clearly identify the WL electronic states. Specifically for the InP/GaAs QDs, the WL and QD recombination overlap as a single PL band. Photomodulated transmission spectroscopy (PT) showed spectral structure consistent with the QD and WL assignments given after the PL analysis.
- Modulation spectroscopy
- Quantum dots