Numerical comparison of quantum-confined Stark effect on emission spectra between InP- and CdSe-based colloidal quantum dots

We numerically compare the quantum-confined Stark effect (QCSE) on emission spectra between InP/ZnSe/ZnS and CdSe/ZnSe/ZnS colloidal quantum dots (QDs). Because the bandgap energy of InP is greater than that of CdSe, the total layer thickness of an InP/ZnSe/ZnS QD is determined to be less than that...

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Bibliographic Details
Published in:Journal of the Korean Physical Society 2023-11, Vol.83 (10), p.769-779
Main Authors: Jang, Deokho, Kim, Jungho
Format: Article
Language:English
Subjects:
Cadmium selenides
Electric fields
Emission spectra
Energy levels
Excitons
Finite element method
Mathematical analysis
Mathematical and Computational Physics
Original Paper - Condensed Matter
Particle and Nuclear Physics
Physics
Physics and Astronomy
Quantum dots
Schrodinger equation
Spectral emissivity
Stark effect
Theoretical
Thickness
Zinc selenide
Zinc sulfide
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Summary:We numerically compare the quantum-confined Stark effect (QCSE) on emission spectra between InP/ZnSe/ZnS and CdSe/ZnSe/ZnS colloidal quantum dots (QDs). Because the bandgap energy of InP is greater than that of CdSe, the total layer thickness of an InP/ZnSe/ZnS QD is determined to be less than that of a CdSe/ZnSe/ZnS QD for both QDs to have the same emission peak wavelength of 563 nm. After strain-modified band-edge energies for electron and heavy hole are calculated, a three-dimensional Schrödinger equation is numerically solved based on the finite element method. The changes in ground-state energy levels, wave-function overlap integrals, and exciton binding energies of the thick CdSe-based QD are much greater than those of the thin InP-based QD when the external electric field intensity increases from 0 to 100 kV/cm. In calculated emission spectra, the CdSe-based QD shows the integrated emission intensity reduction of 6% and ground-state emission peak shift of 0.91 nm. In contrast, the integrated emission intensity decreases by 0.02% and its ground-state emission peak shifts by 0.06 nm for the InP-based QD. Because the degree of the QCSE is proportional to the size of QDs, the emission spectrum of thin InP-based QDs is less sensitive to the QCSE than that of thick CdSe-based QDs when they have the similar peak emission wavelength.
ISSN:0374-4884
1976-8524
DOI:10.1007/s40042-023-00945-0