Composition, volume, and aspect ratio dependence of the strain distribution, band lineups and electron effective masses in self-assembled pyramidal In1−xGaxAs/GaAs and SixGe1−x/Si quantum dots

Califano, Marco; Harrison, P.

doi:10.1063/1.1410318

Cited by 42 publications

(21 citation statements)

References 29 publications

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“…In order to assign transitions from ensemble QDs, calculations based on three-dimensional EMA have been performed. The para- meters used in the calculation are from the observation of AFM images and the parameters published in literature [22,23]. The theoretical calculation results are in good agreement with the experimental results, and they have been listed in Table 1.…”

Section: Article In Presssupporting

confidence: 63%

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Piezomodulated reflectance study of self-assembled InAs quantum dots-in-a-well

Wang¹,

Chen²,

Tang³

et al. 2006

Journal of Crystal Growth

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Section: Article In Presssupporting

confidence: 63%

“…Then the potential distribution of conductive band-edge within eight-band KP theory model derived by Califano et al [23] can be expressed as…”

Section: Theorymentioning

confidence: 99%

Piezomodulated reflectance study of self-assembled InAs quantum dots-in-a-well

Wang¹,

Chen²,

Tang³

et al. 2006

Journal of Crystal Growth

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“…For the electron, heavy hole and light hole, the expressions of V strain are given by the following three equations [21]:…”

Section: Theoretical Modelmentioning

confidence: 99%

Strain distribution and electronic structures of the InAs/GaAs quantum ring molecule in an applied electric field

Jia

Liu

et al. 2010

Sci. China Phys. Mech. Astron.

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The strain distribution and electronic structures of the InAs/GaAs quantum ring molecule are calculated via the finite element method. In our model, three identical InAs quantum rings are aligned vertically and embedded in the cubic GaAs barrier. Considering the band edge modification induced by the strain, the electronic ground state and the dependence of ground state energy on geometric parameters of the quantum ring molecule are investigated. The change of localization of the wavefunction resulting from the applied electric field along the growth direction is observed. The ground state energy decreases as the electric field intensity increases in a parabolic-like mode. The electric field changes the monotonic dependence of the energy level on the inter-ring distance into a non-monotonic one. However, the electric field has no effect on the relationships between the energy level and other geometric parameters such as the inner radius and outer radius. strain distribution, electronic structure, quantum ring molecule, applied electric field PACS: 68.65.Hb, 73.21.La, 81.40.JjNanostructures such as quantum dots and quantum rings have been subjects of great interests for their application in optoelectronic devices [1][2][3][4][5]. Besides the single nanostructure, artificial molecules consisting of quantum dots or rings are particularly attractive because they are promising in quantum information processing [6] and terahertz devices [7]. Recently, the coupled quantum dot molecules and quantum ring molecules have been produced by many groups [8][9][10][11]. For these nanostructures, the formation, evolution and photoluminescence are experimentally studied [8,12,13] while the electronic structures and excitonic properties are theoretically calculated [14-16]. In particular, within the above works, Granados et al. studied the vertical order and the optical properties of stacked quantum rings composed of three layers [8]. Excitonic properties of vertical coupled In(Ga)As/GaAs triple quantum ring molecule [15] and InP/InGaP triple quantum dot molecule [16] theoretically studied by Tadić et al. are also of great interests.In the growth of vertically-stacked lattice-mismatched heterostructures, such as InAs/GaAs quantum dots or rings, the strain plays an important role in aligning the dots or rings in different layers. Compared with a quantum well superlattice, the strain in stacked quantum dots or rings is non-uniform and penetrates into the barrier, which has notable effects on electronic structures. Besides the quantum confinement and the strain distribution, external potential is another factor that determines the energy levels of the electron or hole in the heterostructure. When the heterostructure is placed in an electric or magnetic field with a certain intensity, the bound state energies of the electron and hole will change considerably. Moreover, the Stark effect [17,18] or the Aharonov-Bohm oscillation [19,20] can be observed by applying an electric or magnetic field, respectively.In this article, we investigate ...

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“…( ) QD χ ξ is the Fourier transform of the dot characteristic function, which is equal to 1 inside the dot and 0 outside. For spherical, cubical, pyramidal, truncated pyramidal shaped QD, it can be written respectively as [15,16] 2 4 sin( )…”

Section: A Strain Distributionmentioning

confidence: 99%

Theoretical calculation of quantum-confined stark effect in InAs/GaAs self-assembled quantum dots

2005

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A recent experiment on Stark effect spectroscopy in self-assembled quantum dots (SADs) has demonstrated the existence of an inverted electron-hole alignment due to the presence of gallium diffusion in InAs SADs and has established a relation between the Stark shift and the vertical electron-hole separation. The theoretical interpretation of these experimental results is based on the assumption that the applied electric field can be treated by the second-order perturbation theory, which results in a quadratical dependence of the transition energy on the applied electric field. While this relation is well satisfied in many quantum systems including single SADs and quantum well structures. But this relation is not valid for vertically coupled SAD structures, the asymmetric Stark shift of experimental measurement has shown existence of built-in dipole moment in InAs/GaAs QDs. Here we present a theoretical investigation of the factors influencing the sign and magnitude of the built-in dipole moment in realistic QD structures, including cubical, pyramidal and truncated pyramidal shape. The comparable results gave a reasonable interpretation for the experimental results.Our calculations consist of two basic steps. First, the strain is calculated for particular dot geometry with Green function methods. Second, the single-electron states are calculated using an electronic Hamiltonian, which depends on the strain. The computed states can then be used to determine various quantities, such as optical transition strengths, or exciton binding energies. In the article, we use Green function for the strain calculation, and plane-waves expansion in the envelope function approximation for the electronic structure calculations. The theoretical results agree well with the available experimental data. Our calculated results are useful for the application of QDs to photoelectric devices.

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Composition, volume, and aspect ratio dependence of the strain distribution, band lineups and electron effective masses in self-assembled pyramidal In1−xGaxAs/GaAs and SixGe1−x/Si quantum dots

Cited by 42 publications

References 29 publications

Piezomodulated reflectance study of self-assembled InAs quantum dots-in-a-well

Piezomodulated reflectance study of self-assembled InAs quantum dots-in-a-well

Strain distribution and electronic structures of the InAs/GaAs quantum ring molecule in an applied electric field

Theoretical calculation of quantum-confined stark effect in InAs/GaAs self-assembled quantum dots

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