Chalcogenide

Chalcogenide

From 3D to 2D and Beyond
Woodhead Publishing Series in Electronic and Optical Materials
2020, Pages 153-187
Chalcogenide

6 - Epitaxial II-VI semiconductor quantum structures involving dilute magnetic semiconductors

https://doi.org/10.1016/B978-0-08-102687-8.00009-9Get rights and content

Abstract

Magneto-optical properties were studied on ultrathin MBE-grown ZnTe and ZnSe epilayers by observing hydrogenic exciton series up to 2s states in the absence of the magnetic field and by observing Landau level transitions in the magnetic field. The band structure of ZnSeTe superlattice with sinusoidal energy profiles was investigated by using nearly-free-electron (NFE) approximation. The analysis revealed that the minigap is determined only by the value of the band offset of the sinusoidal superlattice. The quantum effect arising from such band structures of sinusoidal superlattice was observed in photoluminescence spectrum, which shifted to lower energy relative to the corresponding alloy system. The quantum effect was further investigated in the zero-dimensional geometries -- the so called “quantum dots” (QDs) -- in which the motion of carriers and/or excitons are confined in all three directions. The characteristics of QD system was observed via thermal stability and narrow linewidth of optical transition. The degree of wavefunction localization in the QDs was mapped by involving diluted magnetic semiconductor, which showed extremely large Zeeman splitting of electronic levels, in the QD system. The spin-spin interaction in coupled QD system was further investigated by using double layer QD (DLQD) structure consists of DMS (ZnCdMnSe) and non-DMS (CdZnSe) QDs with non-DMS (ZnSe) barriers. The twice larger spin polarization of carriers in non-DMS CdZnSe QDs was observed in DLQD system compared to that of single layer CdZnSe DQs, indicating significant enhancement of spin polarization due to the presence of highly spin-polarized carriers in DMS QDs.

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  • Effects of geometry and electric and magnetic fields on the thermal properties of two-dimensional semiconducting nanoporous superlattices

    2021, Journal of Physics and Chemistry of Solids
    Citation Excerpt :

    Previous studies have determined the optical properties of ZnSe1-xTex sinusoidal superlattices [59] and their optical properties in the presence of Rashba spin–orbit interactions [60], as well as their Floquet states [61], and comparisons have been conducted of the electron energy versus the wave vector for square-well systems [62]. The electronic band structure of sinusoidal superlattices is also unique because it contains a single minigap that separates two wide free electron-like subbands, which is true for both electrons and holes [58]. The electronic states of Cd1−xZnxS flattened cylindrical QD superlattices [63] have also been considered.

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