Evolution from individual to collective electron states in a dense quantum dot ensemble

Artemyev, Mikhail; Bibik, A. I.; Gurinovich, L. I.; Гапоненко, С. В.; Woggon, U.

doi:10.1103/physrevb.60.1504

Cited by 174 publications

(153 citation statements)

References 20 publications

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“…Such a strong PL peak of the dense GeSi QDs on miscut substrates indicates that the dense QDs may have superior optoelectronic properties. Theoretical calculation indicates that the strong coupling among dense QDs can give rise to the unique collective properties 29 and the carrier multiplication effect. 30 The dense QDs readily obtained on the slightly miscut substrates can be promising candidates for the exploration of the unique properties of QDs due to the quantum confinement effect and the strong interaction.…”

Section: -2mentioning

confidence: 99%

Dramatically enhanced self-assembly of GeSi quantum dots with superior photoluminescence induced by the substrate misorientation

Zhou

Zhong

2014

APL Materials

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A dramatically enhanced self-assembly of GeSi quantum dots (QDs) is disclosed on slightly miscut Si (001) substrates, leading to extremely dense QDs and even a growth mode transition. The inherent mechanism is addressed in combination of the thermodynamics and the growth kinetics both affected by steps on the vicinal surface. Moreover, temperature-dependent photoluminescence spectra from dense GeSi QDs on the miscut substrate demonstrate a rather strong peak persistent up to 300 K, which is attributed to the well confinement of excitons in the dense GeSi QDs due to the absence of the wetting layer on the miscut substrate.

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Section: -2mentioning

confidence: 99%

Dramatically enhanced self-assembly of GeSi quantum dots with superior photoluminescence induced by the substrate misorientation

Zhou

Zhong

2014

APL Materials

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“…Recently, we used the TB approach to successfully explain (i) optical spectra and the appearance of dark excitons in multishell quantum dot-quantum wells [20,21] and (ii) coupling effects in artificial molecules and close-packed arrays formed by chemically synthesized nanocrystals [22][23][24]. It has been shown [20] that level ordering, splitting, and degeneracy can depend on atomic-scale details, like the definition of quantum dot center (at an anion, a cation, or at midbond).…”

Section: Theorymentioning

confidence: 99%

Coupling and Strain Effects in Vertically Stacked Double InAs/GaAs Quantum Dots: Tight-Binding Approach

2004

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The empirical tight-binding approach is used to study atomic-scale effects on electronic coupling in vertically stacked, self-assembled InAs/GaAs quantum dots. A model with unstrained dots is first studied to isolate the atomistic coupling effects from the strain effects. The strain effects are next considered by means of the valence force field method. Electron levels in coupled quantum dots follow closely the simple analogy of coupled dots as artificial molecules. The electron ground state of double dot has always bonding-like character. The coupling of hole states is more complicated because the coupling depends both of the hole envelope function and the atomic character of the hole state. It is shown that the character of the hole ground state of double dot changes from antibonding to bonding-like, when the distance between the dots decreases. It reorders hole levels, changes state symmetries, and makes changes in optical spectra. The calculated red-shift of the lowest transition for closely-spaced dots agrees well with experimental data. We present also some preliminary results on strain effects in such nanocrystals.

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“…5 It is important to note that while the optoelectronic properties of lowdimensional semiconductors have been investigated widely 6,7 this is one of the few studies on dense ensembles of QDs or QDSs. 8,9 A major problem with isolated semiconductor nanoparticles is that they often have surface electronic states within the highest occupied molecular orbital/lowest unoccupied molecular orbital ͑HOMO-LUMO͒ gap that provide nonradiative decay channels and lead to a severe degradation in optoelectronic properties. This problem has been addressed by "capping" the semiconductor nanoparticle with a thin layer of a higher band gap material.…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence enhancement in nanocomposite thin films of CdS–ZnO

Ayyub

Vasa

Taneja

et al. 2005

Journal of Applied Physics

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We show that the photoluminescence emitted from a dense, two-component quantum dot ensemble on a thin film is significantly higher and decays much faster than that from quantum dots of either of the two pure systems ͑CdS and ZnO͒. The semiconductor nanocomposite, in which the characteristic grain size of each species was 2 -3 nm, was deposited directly on Si wafers by high-pressure magnetron sputtering, and exhibits a single, relatively sharp optical absorption edge.

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Evolution from individual to collective electron states in a dense quantum dot ensemble

Cited by 174 publications

References 20 publications

Dramatically enhanced self-assembly of GeSi quantum dots with superior photoluminescence induced by the substrate misorientation

Dramatically enhanced self-assembly of GeSi quantum dots with superior photoluminescence induced by the substrate misorientation

Coupling and Strain Effects in Vertically Stacked Double InAs/GaAs Quantum Dots: Tight-Binding Approach

Photoluminescence enhancement in nanocomposite thin films of CdS–ZnO

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