Exciton fine structure in CdSe nanoclusters

Leung, Kevin; Whaley, K. Birgitta

doi:10.1103/physrevb.57.12291

Cited by 126 publications

(148 citation statements)

References 45 publications

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“…The same structures have been used in previous time-independent tight-binding studies. 14,19,21 We remove the dangling bonds on the surface by shifting the energies of the corresponding hybrid orbitals well above the conduction band edge. The spin-orbit interaction is included in the Hamiltonian.…”

Section: A Tight-binding Model Of Cdse Nanostructurementioning

confidence: 99%

Magneto-optical response of CdSe nanostructures

Chen

Whaley

2004

Phys. Rev. B

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We present theoretical calculations of the Landé g-factors of semiconductor nanostructures using a time-dependent empirical tight-binding method. The eigenenergies and eigenfunctions of the band edge states are calculated as a function of an external magnetic field with the electromagnetic field incorporated into the tight-binding Hamiltonian in a gauge-invariant form. The spin-orbit interaction and magnetic field are treated non-perturbatively. The g-factors are extracted from the energy splitting of the eigenstates induced by the applied magnetic field. Both electron and hole gfactors are investigated for CdSe nanostructures. The size and aspect ratio dependence of g-factors is studied. We observe that the electron g-factors are anisotropic and find that the calculated values agree quantitatively with experimental data. We conclude that the two distinct g-factor values extracted from time resolved Faraday rotation experiments should be assigned to the anisotropic in plane (g ) and out of plane (gz) electron g-factors, rather than to isotropic electron and exciton g-factors. We find that the anisotropy in the electron g-factor depends on the aspect ratio of the nanocrystal. The g-factor anisotropy derived from the wurtzite structure and from the non-unity aspect ratio may cancel each other in some regime. We observe that hole g-factors oscillate as a function of size, due to size dependent mixing between the heavy hole-light hole components of the valence band edge states. Extension to the calculation of exciton g-factors is discussed.

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Section: A Tight-binding Model Of Cdse Nanostructurementioning

confidence: 99%

Magneto-optical response of CdSe nanostructures

Chen

Whaley

2004

Phys. Rev. B

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“…Extensive work has been devoted to detailed comparison of theory of quantum confined electronic states in these nanocrystals with experiments in which the diameter of spherical dots is varied [5][6][7][8][9][10][11][12][13] . Early phenomenological models are based on the effective mass approximation [7][8][9][10] ; later developments include tight-binding models 11,12 and empirical pseudo-potential calculations 13 . Each of these models can provide an adequate description of the band-gap variation versus diameter for spherical or nearly spherical dots, and they also provide varying levels of success in describing higher electronic excited states.…”

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confidence: 99%

Band Gap Variation of Size- and Shape-Controlled Colloidal CdSe Quantum Rods

et al. 2001

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“…In the quantum confinement regime, the size and shape of semiconductor NCs also have an impact on the exciton fine-structure. The exciton fine-structure is the way in which the energy states of the exciton are split by effects of the crystal field asymmetry, NC shape anisotropy, and electron-hole exchange interaction [36][37][38]. Exciton fine-structure splitting is analogous to singlet-triplet splitting in organic molecules, but the energy splittings for an exciton in a NC are typically smaller, namely only a few meV.…”

Section: Quantum Confinement Effects: Squeezing and Shaping Nanoscalementioning

confidence: 99%

“…These effects are beyond the scope of this review. The interested reader is referred to a number of publications addressing this topic in detail [36][37][38][39][40][41][42][43][44][45][46][47][48]. Phonons (i.e., lattice vibrations) have a pervasive role in semiconductors, and therefore coupling of charge carriers and excitons to phonons plays a decisive role in a wide range of properties [49].…”

Section: Quantum Confinement Effects: Squeezing and Shaping Nanoscalementioning

confidence: 99%

Excited-State Dynamics in Colloidal Semiconductor Nanocrystals

Rabouw

Donegá

2016

Topics in Current Chemistry Collections

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Colloidal semiconductor nanocrystals have attracted continuous worldwide interest over the last three decades owing to their remarkable and unique sizeand shape-, dependent properties. The colloidal nature of these nanomaterials allows one to take full advantage of nanoscale effects to tailor their optoelectronic and physical-chemical properties, yielding materials that combine size-, shape-, and composition-dependent properties with easy surface manipulation and solution processing. These features have turned the study of colloidal semiconductor nanocrystals into a dynamic and multidisciplinary research field, with fascinating fundamental challenges and dazzling application prospects. This review focuses on the excited-state dynamics in these intriguing nanomaterials, covering a range of different relaxation mechanisms that span over 15 orders of magnitude, from a few femtoseconds to a few seconds after photoexcitation. In addition to reviewing the state of the art and highlighting the essential concepts in the field, we also discuss

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Exciton fine structure in CdSe nanoclusters

Cited by 126 publications

References 45 publications

Magneto-optical response of CdSe nanostructures

Magneto-optical response of CdSe nanostructures

Band Gap Variation of Size- and Shape-Controlled Colloidal CdSe Quantum Rods

Excited-State Dynamics in Colloidal Semiconductor Nanocrystals

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