Temperature dependence of the optical properties of InAs quantum dots with bimodal size evolution grown on GaAs (1 1 5)A substrate

A self-assembled InAs quantum dots (QDs) were grown on GaAs (1 1 5)A substrate by molecular beam epitaxy at a growth temperature of 500 °C and using two growth rates. The photoluminescence (PL) has been studied for the ensembles of InAs QDs embedded in GaAs matrix to investigate the interband transition energies. Distinctive double-peak feature was observed in the PL spectra of the QD sample elaborated at the relatively low growth rate. Temperature-dependent PL study was carried out in the 10–300 K temperature range. From the excitation power-dependent PL and the temperature-dependent PL measurements, the double-peak feature is associated with the ground-state transitions from InAs QDs with two different families of dots (different size). It is found that the full width at half-maximum (FWHM), for the two samples, first decreases and then increases with increasing temperature. This was attributed to the thermalized carriers repopulate the QDs of larger sizes representing deeper potential wells.