Abnormal temperature dependencies of photoluminescence and carrier transfer in InAs QDs and DWELL structures grown on GaAs (1 1 5)A emitting near 1.3 µm wavelength

In this work, an optical comparative study of InAs quantum dots (QDs) and InAs/In0.25Ga0.75As dot-in-well (DWELL) grown by molecular beam epitaxy on GaAs (1 1 5)A substrate has been carried out. Emission peak at 1.3 µm has been achieved from the DWELL sample. It is found that a monotonical decrease of the integrated PL intensity and the FWHM has taken place, with an increasing temperature up to 270 K for the QDs sample. However, we observe an unusual increase of the FWHM and an invariant integrated PL intensity in the range of temperature (60–150 K). We have attributed this result to two mechanisms: the acoustic–phonon interaction and the tunnel escaping carriers among the inhomogeneous dots size via the piezoelectric field. Theoretical modeling procedure has been applied to analyse the ground state PL peak position evolution as a function of temperature using three models (Varshni, “Vina, Logothetidis and Cardona”, and Passler). The comparison between theoretical and experimental data revealed that the PL contribution of the inhomogeneous size of quantum dots takes place only for temperatures higher than 160 K. These results can help improve our understanding of some fundamental properties of DWELL and QDs grown on the GaAs high index substrates.