Abstract
We have studied the parallel and perpendicular electric field effects on the system of SiGe prolate and oblate quantum dots numerically, taking into account the wetting layer and quantum dot size effects. Using the effective-mass approximation in the two bands model, we computationally calculated the extensive variation of dipole matrix (DM) elements, bandgap and non-linear optical properties, including absorption coefficients, refractive index changes, second harmonic generation and third harmonic generation as a function of the electric field, wetting layer size and the size of the quantum dot. The redshift is observed for the non-linear optical properties with the increasing electric field and an increase in wetting layer thickness. The sensitivity to the electric field toward the shape of the quantum dot is also observed. This study is resourceful for all the researchers as it provides a pragmatic model by considering oblate and prolate shaped quantum dots by explaining the optical and electronic properties precisely, as a consequence of the confined stark shift and wetting layer.
Highlights
The science of zero-dimensional semiconductor nanomaterial structures, quantum dots (QDs), has revolutionized the research of fabrication of optoelectronic devices as they have exquisite optical and electronic properties [1,2,3]
The parameters used in the numerical calculations for SiGe are as follows: σ = 2.8 × 1025 m−3, the electron density, nr (η = 0.3) = 3.55 represents the refractive index of the QD, ε(η = 0.3) = 13.05 is the static dielectric constant, Γif = 0.38 ps−1 is the inverse of the relaxation time material and I = 2 × 107 W/m2 is the intensity of the incident electromagnetic field [59,67]
Our analysis showed that the redshift is caused by the energy levels of the electric field and increased size of the QD
Summary
The science of zero-dimensional semiconductor nanomaterial structures, quantum dots (QDs), has revolutionized the research of fabrication of optoelectronic devices as they have exquisite optical and electronic properties [1,2,3]. By using the effective mass and parabolic band approximations, they have determined analytically the energies of the fundamental and few low lying states of a single electron confined in a paraboloidal quantum lens [25] They further studied the Stark effect and the polarizability of shallow-donor impurity located in the center of a lens-shaped QD by a variational method [26]. In Reference [28], with the adiabatic approximation, the electron states and light absorption are investigated for the study of strongly oblate and strongly prolate ellipsoidal QDs in the presence of electrical and magnetic fields. We have investigated the effect of the electric field and WL in prolate and oblate QDs for Si1−η Geη material for η = 0.3 for the WL surrounded by Si matrix with varying size. We have concluded our results in the final section of the conclusion
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