A comparative study of analog, digital, and linear alloy technique on the strain and optical properties of symmetrical InGaAs/InAs/InGaAs quantum dot-in-a-well (DWELL) heterostructure

In this study, the author proposed a new technique for strain minimization, called linear alloy technique (LAT), for the symmetric dot-in-a-well (DWELL) heterostructure. Here, three different DWELL InAs QDs heterostructures with 6 nm thick InxGa1-xAs as well material have been simulated using 8 band k.p. model-based Nextnano software. Here, the first sample is analog alloyed DWELL heterostructure having In0.15Ga0.85As well (Sample A), the second sample is digital alloyed DWELL heterostructure where the well layer is divided into three sub-layers of 2nm thickness with indium composition varied from 45% to 15% in the step of 15%(Sample D), and the third sample is linear alloyed DWELL heterostructure where indium composition is varied from 45% to 15% (Sample L) in linear fashion have been studied. The Lower the magnitude of hydrostatic strain better will be carrier confinement. The more the biaxial strain, the more the heavy-hole and light-hole band splitting, which reduces the transition energy gap. The computed biaxial strain is increased by 1.52% and 2.21%, and the magnitude of hydrostatic strain is reduced by 3.66% and 1.13% in sample Lcompared with samples A and D, respectively. Strain inside the well layer of sample L reduces more smoothly than samples A and D, respectively. The computed PL emission wavelength for all three samples are 1329, 1418, and 1419 nm for the samples A, D, and L, respectively. Hence, this proposed technique can be the best choice for fabricating future optoelectronicbased devices.