Strain-engineering of GaInAsSb overgrown layers and its effects on the optical properties of InAs/GaAs quantum dots

The effect of antimony incorporation in In_0.11Ga_0.89As overgrown layers on the optical properties of InAs/GaAs quantum dots grown by molecular beam epitaxy has been studied. The results of photoluminescence, high resolution X-ray diffraction, atomic force microscopy, power and temperature-dependent photoluminescence from 77 K to 300 K have been correlated to characterize the grown samples. The wavelength emission increases with Sb content, and it reaches ∼1367 nm and does not increase further because of Sb incorporation's saturation in the In_0.11Ga_0.89As layer. To redshift further the wavelength to 1432 nm, a reduction of the growth temperature of the In_0.11Ga_0.89As_1-ySb_y layer from 500 °C to 440 °C was necessary. This achievement is accompanied by the transformation of the QDs distribution to 2 QDs families. The extracted activation energies suggest that the PL quenching is mainly attributed to the thermal transfer of carriers in the QDs to the higher energy levels in the defects located within the In_0.11Ga_0.89As_1-ySb_y SRLs. The variation of PL FWHM with temperature was interpreted by carrier thermalization and capture among different QDs within the same QD family or between small and large QD families.