Effect of growth rate variations of 3ML SK quantum dot coverage in DWELL heterostructures on the strain and optical properties

Self-assembled InAs quantum dot heterostructures have been employed as a promising entrant for various optoelectronic device applications over the past few decades. This is because of their properties such as 3D carrier quantum confinement, normal incidence photon absorption, etc. In this work, we have qualitatively studied the effect of growth rate variations of MBE-grown 3ML SK QD in DWELL heterostructures on their optical and strain behaviour. Three samples A, B, and C with a growth rate of 0.1ML/s, 0.075ML/s, and 0.05ML/s with growth time 30s, 40s, and 60s, respectively have been considered. The bottom and top In_0.15Ga_0.85As well thickness is kept constant at 2nm and 6nm respectively. From the optical study, it has been observed that the PL emission wavelength of structures A, B, and C was approximately 1045nm, 1054nm, and 1071nm respectively. Also, the observed PL intensity of sample C is almost three times that of sample A. This is due to the homogeneous dot formation in sample C which has a low growth rate and promotes uniform dot sizes. From the simulation results, it has been observed a significant improvement in hydrostatic and biaxial strain of sample C as compared to that of samples A and B. The simulated PL spectra for samples A, B, and C were also calculated to be 1053nm, 1052nm, and 1082nm respectively. Hence, sample C with high PL intensity can be utilized for SWIR optoelectronic applications.