An investigation of growth temperature on the surface morphology and optical properties of 1.3 μm InAs/InGaAs/GaAs quantum dot structures

We have investigated the surface morphology and optical properties of InAs/InGaAs/GaAs quantum dots grown at 450, 480 and 510 degrees C. While the performances of QD devices utilizing InAs/InGaAs/GaAs structures have been well- documented, there have not been many research efforts on the growth optimization of InAs/InGaAs/GaAs QDs. We found that, unlike InAs/ GaAs QD structures, InAs/ InGaAs/ GaAs QD structures benefit from a lower QD growth temperature. Evidence from the photoluminescence (PL) spectra suggests a decreasing presence of nonradiative islands and a multi- modal size distribution following the decrease in the growth temperature. Strong room temperature PL emission at 1.32 mu m with a narrow full- width at half-maximum (FWHM) of 27.8 meV was obtained from the InAs/InGaAs/GaAs QD structure grown at 450 degrees C, as verified by the large areal density and narrow dot size distribution. This work indicates the feasibility of obtaining good surface morphology and optical properties at a low growth temperature for InAs/InGaAs/GaAs QD structures.