Exciton states in CdSe/ZnS core–shell quantum dots under applied electric fields

Niculescu, E.C.; Cristea, M.; Spandonide, Ana

doi:10.1016/j.spmi.2013.08.005

Cited by 29 publications

(13 citation statements)

References 33 publications

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“…A formula arises from the existence of the polarized surface charges at the dot boundary and describes the interaction between the ion and electron [28]. W(r) term in formula (1) describes the electron self-polarization potential, which in the case of a small difference between ε 1 and ε 2 is simplified to the following form [27,28]…”

Section: Theoretical Modelmentioning

confidence: 99%

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Optical properties of GaAs/Al_{x}Ga_{1-x}As/GaAs quantum dot with off-central impurity driven by electric field

Holovatsky¹,

Yakhnevych²,

Voіtseкhіvsкa³

2018

Condens. Matter Phys.

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The effect of a constant electric field and donor impurity on the energies and oscillator strengths of electron intraband quantum transitions in double-well spherical quantum dot GaAs/Al x Ga 1−x As/GaAs is researched. The problem is solved in the framework of the effective mass approximation and rectangular potential wells and barriers model using the method of wave function expansion over a complete set of electron wave functions in nanostructure without electric field. It is shown that under the effect of electric field, the electron in the ground state tunnels from the inner potential well into the outer one. It also influences on the oscillator strengths of intraband quantum transition. The binding energy of an electron with ion impurity is obtained as a function of electric field intensity at a different location of impurity.

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Section: Theoretical Modelmentioning

confidence: 99%

“…That is manifested by the optical properties and can be used in new optoelectronic devices. The effect of electric field on quasi-particles energy spectra in spherical nanostructures with one potential well is investigated in [18,26,27].…”

Section: Introductionmentioning

confidence: 99%

Optical properties of GaAs/Al_{x}Ga_{1-x}As/GaAs quantum dot with off-central impurity driven by electric field

Holovatsky¹,

Yakhnevych²,

Voіtseкhіvsкa³

2018

Condens. Matter Phys.

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“…According to the literature, QDs with different shapes such as elliptical-shaped [21], spherical-shaped [22], ring-shaped, cylindrical-shaped [23] and pyramidal-shaped [24] have been investigated to describe the 3D confinement in GaAs systems. Recently, more attention has been focused on the quantum ring structures because of their import roles in electric and optical properties [25][26][27][28][29]. Spin is an intrinsic feature of charge carriers that makes the system sensitive to external factors like magnetic fields due to the spin-orbit couplings.…”

Section: Introductionmentioning

confidence: 99%

Tuning Absorption coefficient and refractive index changes in GaAs quantum ring Under Combined Effects of Temperature, Pressure, Rashba and Dresselhaus spin-orbit couplings

Hasanirokh

2023

Preprint

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In the present work, we have explored how the pressure, temperature and size of a GaAs quantum ring in the presence of Rashba and Dresselhaus spin–orbit couplings (SOC) can affect the energy states, dipole transition matrix elements (DTMEs), optical absorption coefficients (OACs) and refractive index changes (RICs). In addition to the theoretical beauty of this important and exciting area of research, it represents the attractive potential applications in the growth of optoelectronics devices. The results have indicated that the ground state energy values rise with pressure and Dresselhaus coupling. Meanwhile, increasing the temperature and Rashba coupling as well as the ring’s size leads to a decrement of energy levels. Taking the transition from the ground state to the first excited state, we have found that the temperature, pressure, inner and outer radius decrease DTMEs because of a drop in wave functions overlap. Therefore, the presence of SOCs, pressure, temperature and dimensions of the quantum ring dominate the electronic behavior and consequently control the absorption as well as the refractive index of the nano structure. A significant enhancement of the OACs and RICs curves is witnessed when the pressure, ring geometric, and Rashba strength are enlarged, but Increasing Dresselhaus coefficient decreases OACs and RICs. These parameters are responsible for blue shifts in the optical absorption. These results can be suitable in the construction of spin-based devices.

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“…Quantum dots demonstrate unique properties such as high quantum yield, narrow symmetric luminescence peak and high photostability, which are used in optical molecular sensor systems [ 1 ], bioanalysis [ 2 ], solar cells [ 3 – 4 ], and light-emitting devices [ 5 ]. The application of external electric fields to semiconductor NPs significantly changes their optical properties [ 6 – 10 ]. To control the properties of NPs, they are introduced into a passive or active matrix interacting with them.…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence of CdSe/ZnS quantum dots in nematic liquid crystals in electric fields

Kurochkina

Konshina

Khmelevskaia

2018

Beilstein J. Nanotechnol.

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We have experimentally investigated the effect of the reorientation of a nematic liquid crystal (LC) in an electric field on the photoluminescence (PL) of CdSe/ZnS semiconductor quantum dots (QDs). To the LC with positive dielectric anisotropy, 1 wt % QDs with a core diameter of 5 nm was added. We compared the change of PL intensity and decay times of QDs in LC cells with initially planar or vertically orientated molecules, i.e., in active or passive LC matrices. The PL intensity of the QDs increases four-fold in the active LC matrix and only 1.6-fold in the passive LC matrix without reorientation of the LC molecules. With increasing electric field strength, the quenching of QDs luminescence occurred in the active LC matrix, while the PL intensity did not change in the passive LC matrix. The change in the decay time with increasing electric field strength was similar to the behavior of the PL intensity. The observed buildup in the QDs luminescence can be associated with the transfer of energy from LC molecules to QDs. In a confocal microscope, we observed the increase of particle size and the redistribution of particles in the active LC matrix with the change of the electric field strength. At the same time, no significant changes occurred in the passive LC matrix. With the reorientation of LC molecules from the planar in vertical position in the LC active matrix, quenching of QD luminescence and an increase of the ion current took place simultaneously. The obtained results are interesting for controlling the PL intensity of semiconductor QDs in liquid crystals by the application of electric fields.

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Exciton states in CdSe/ZnS core–shell quantum dots under applied electric fields

Cited by 29 publications

References 33 publications

Optical properties of GaAs/Al_{x}Ga_{1-x}As/GaAs quantum dot with off-central impurity driven by electric field

Optical properties of GaAs/Al_{x}Ga_{1-x}As/GaAs quantum dot with off-central impurity driven by electric field

Tuning Absorption coefficient and refractive index changes in GaAs quantum ring Under Combined Effects of Temperature, Pressure, Rashba and Dresselhaus spin-orbit couplings

Photoluminescence of CdSe/ZnS quantum dots in nematic liquid crystals in electric fields

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