Tuning of polarization sensitivity in closely stacked trilayer InAs/GaAs quantum dots induced by overgrowth dynamics

Tasco, V.; Usman, Muhammad; Giorgi, Milena De; Passaseo, A.

doi:10.1088/0957-4484/25/5/055207

Cited by 8 publications

(1 citation statement)

References 43 publications

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“…Therefore we have ignored this effect in our simulations. However, our recent studies 46,47 have indicated that the In-Ga intermixing has a minor impact on the confinements and symmetries of the electron and hole wave functions for the single and trilayered QD systems. Consequently, we expect that the presented physical insights will remain valid in the presence of weak In-Ga intermixings.…”

Section: Theoretical Frameworkmentioning

confidence: 96%

Understanding the electric field control of the electronic and optical properties of strongly-coupled multi-layered quantum dot molecules

Usman

2015

Nanoscale

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Strongly-coupled quantum dot molecules (QDMs) are widely deployed in the design of a variety of optoelectronic, photovoltaic, and quantum information devices. An efficient and optimized performance of these devices demands engineering of the electronic and optical properties of the underlying QDMs. The application of electric fields offers a knob to realise such control over the QDM characteristics for a desired device operation. We perform multi-million-atom atomistic tight-binding calculations to study the influence of electric fields on the electron and hole wave function confinements and symmetries, the ground-state transition energies, the band-gap wavelengths, and the optical transition modes. The electrical fields both parallel ( E p ) and anti-parallel ( E a ) to the growth direction are investigated to provide a comprehensive guide on the understanding of the electric field effects. The strain-induced asymmetry of the hybridized electron states is found to be weak and can be balanced by applying a small E a electric field, of the order of 1 KV/cm. The strong interdot couplings completely break down at large electric fields, leading to single QD states confined at the opposite edges of the QDM. This mimics a transformation from a type-I band structure to a type-II band structure for the QDMs, which is a critical requirement for the design of intermediate-band solar cells (IBSC). The analysis of the field-dependent ground-state transition energies reveal that the QDM can be operated both as a high dipole moment device by applying large electric fields and as a high polarizibility device under the application of small electric field magnitudes. The quantum confined Stark effect (QCSE) red shifts the band-gap wavelength to 1.3 µm at the 15 KV/cm electric field; however the reduced electron-hole wave function overlaps lead to a decrease in the interband optical transition strengths by roughly three orders of magnitude. The study of the polarisation-resolved optical modes indicate the benefit of applying small electric fields, which lead to an isotropic polarisation response, a desirable property for the semiconductor optical amplifiers (SOAs).1 arXiv:1508.05981v1 [cond-mat.mes-hall]

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Section: Theoretical Frameworkmentioning

confidence: 96%

Understanding the electric field control of the electronic and optical properties of strongly-coupled multi-layered quantum dot molecules

Usman

2015

Nanoscale

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A qualitative analysis of the impact of P composition in GaAs1−P capped InAs/GaAs quantum dot hetero-structure

Muchahary

Maity

2022

Micro and Nanostructures

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InAs/InP quantum dots stacking: Impact of spacer layer on optical properties

Xiong

Zhang

2019

Journal of Applied Physics

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The optical properties of a vertical multilayer stack of semiconductor self-assembled quantum dots (QDs) depend on the coupling status. We present an improved modeling method for analysis of QD stacks, consisting of several separate steps in the elastic strain analysis, to reproduce the realistic unidirectional strain accumulation along the QD growth direction from lower and upper dots. Based on this modeling method, by varying the spacer thickness, we systematically study a large variety of QD stack structures, for better understanding the influence of strain and electronic coupling mechanisms. A “quasi continuum band” or highly degenerate excited state (ES) is found in the closely multi-stacked QDs, probably accounting for the occurrence of distinct blueshifting of the photoluminescence peak wavelength for the decreasing spacer thickness. The enhanced ES emission from this type of stacking QD modeled by using rate equations may pave a way for designing potential high-performance laser devices operating on ES.

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Tuning of polarization sensitivity in closely stacked trilayer InAs/GaAs quantum dots induced by overgrowth dynamics

Cited by 8 publications

References 43 publications

Understanding the electric field control of the electronic and optical properties of strongly-coupled multi-layered quantum dot molecules

Understanding the electric field control of the electronic and optical properties of strongly-coupled multi-layered quantum dot molecules

A qualitative analysis of the impact of P composition in GaAs1−P capped InAs/GaAs quantum dot hetero-structure

InAs/InP quantum dots stacking: Impact of spacer layer on optical properties

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