The quantum-well (QW) states in the Cu/Co double-well system are studied by first-principles calculations. We have shown that the monolayer Ni or Co as a heterogeneous spacer in Cu QW can not only disturb the QW states extending into the whole structure, but also create new QW states because of the interfaces introduced, resulting in sub-well-confining electrons. If the QW state energy in two sub-wells is close to each other, these two sub-well QW states can couple together. We have also demonstrated that monolayer Co and Ni spacers play different roles for modulating QW states at different energy levels, which also result in a complicated distribution of QW states. The obtained results are in good agreement with experiment data.
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http://dx.doi.org/10.1088/0953-8984/22/5/052203 | DOI Listing |
ACS Nano
January 2025
Beijing Academy of Quantum Information Sciences, Beijing 100193, P. R. China.
The quantum-well-like two-dimensional lead-halide perovskites exhibit strongly confined excitons due to the quantum confinement and reduced dielectric screening effect, which feature intriguing excitonic effects. The ionic nature of the perovskite crystal and the "softness" of the lattice induce the complex lattice dynamics. There are still open questions about how the soft lattices decorate the nature of excitons in these hybrid materials.
View Article and Find Full Text PDFNanotechnology
January 2025
Radiophysics, Tomsk State University, Lenin, 36, Tomsk, Tomsk region, 634050, RUSSIAN FEDERATION.
Structural and photoelectric properties of p-i-n photodiodes based on GeSiSn/Si multiple quantum dots both on Si and silicon-on-insulator (SOI) substrates were investigated. Elastic strained state of grown films was demonstrated by x-ray diffractometry. Annealing of p-i-n structures before the mesa fabrication can improve the ideality factor of current-voltage characteristics.
View Article and Find Full Text PDFNanotechnology
January 2025
Radiophysics, Tomsk State University, Lenin, 36, Tomsk, Tomsk region, 634050, RUSSIAN FEDERATION.
Structural and photoelectric properties of p-i-n photodiodes based on GeSiSn/Si multiple quantum dots both on Si and silicon-on-insulator (SOI) substrates were investigated. Elastic strained state of grown films was demonstrated by x-ray diffractometry. Annealing of p-i-n structures before the mesa fabrication can improve the ideality factor of current-voltage characteristics.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Centro de Investigación en Ciencias-IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico.
The energy positions and wave function shapes of the ground and excited states of impurities, including resonance states, are studied using the expansion of the impurity wave function in basis functions. The structures under study are rectangular GaAs/AlGaAs quantum wells with four different widths. In all cases, the impurity binding energy (relative to the corresponding sub-band) has a maximum at or near the center of the quantum well, decreases as the heterointerface is approached, and apparently has a limit of 0 if the impurity moves deeper into the barrier.
View Article and Find Full Text PDFACS Nano
January 2025
Dto. de Física de Materiales, Universidad Complutense de Madrid, 28040 Madrid, Spain.
We experimentally observe quantum confinement states in bulk MoS by using angle-resolved photoemission spectroscopy (ARPES). The band structure at the Γ̅ point reveals quantum well states (QWSs) linked to vertical quantum confinement of the electrons, confirmed by the absence of dispersion in and a strong intensity modulation with the photon energy. Notably, the binding energy dependence of the QWSs versus does not follow the quadratic dependence of a two-dimensional electron gas.
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