Interface Phonons and Polaron States in Quantum Nanostructures

From the viewpoint of band engineering, the use of GaSb quantum nanostructures is expected to lead to highly efficient intermediate-band solar cells (IBSCs). In IBSCs, current generation via two-step optical excitations through the intermediate band is the key to the operating principle. This mechanism requires the formation of a strong quantum confinement structure. Therefore, we focused on the material system with GaSb quantum nanostructures embedded in AlGaAs layers. However, studies involving crystal growth of GaSb quantum nanostructures on AlGaAs layers have rarely been reported. In our work, we fabricated GaSb quantum dots (QDs) and quantum rings (QRs) on AlGaAs layers via molecular-beam epitaxy. Using the Stranski–Krastanov growth mode, we demonstrated that lens-shaped GaSb QDs can be fabricated on AlGaAs layers. In addition, atomic force microscopy measurements revealed that GaSb QDs could be changed to QRs under irradiation with an As molecular beam even when they were deposited onto AlGaAs layers. We also investigated the suitability of GaSb/AlGaAs QDSCs and QRSCs for use in IBSCs by evaluating the temperature characteristics of their external quantum efficiency. For the GaSb/AlGaAs material system, the QDSC was found to have slightly better two-step optical excitation temperature characteristics than the QRSC.

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Hybrid Perovskite Quantum Nanostructures Synthesized by Electrospray Antisolvent–Solvent Extraction and Intercalation

ACS Applied Materials & Interfaces ◽

10.1021/acsami.5b10208 ◽

2015 ◽

Vol 8 (1) ◽

pp. 854-861 ◽

Cited By ~ 36

Author(s):

Rounak Naphade ◽

Satyawan Nagane ◽

G. Shiva Shanker ◽

Rohan Fernandes ◽

Dushyant Kothari ◽

...

Keyword(s):

Solvent Extraction ◽

Quantum Nanostructures ◽

Hybrid Perovskite

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Self Organized Array of Quantum Nanostructures Via a Strain Induced Morphological Instability

MRS Proceedings ◽

10.1557/proc-707-aa3.3.1/n2.3.1 ◽

2001 ◽

Vol 707 ◽

Author(s):

David Montiel ◽

Judith Müller ◽

Eugenia Corvera Poiré

Keyword(s):

Stability Analysis ◽

Linear Stability Analysis ◽

Morphological Instability ◽

Heteroepitaxial Growth ◽

Dominant Mechanism ◽

Quantum Nanostructures ◽

Spontaneous Formation ◽

Self Organized ◽

Aspect Ratios ◽

Terrace Width

ABSTRACTMotivated by the work of Li et al. [1], we have studied the strain induced morphological instability at the submonolayer coverage stage of heteroepitaxial growth on a vicinal substrate with regularly spaced steps. We have performed a linear stability analysis and determined for which conditions of coverage a flat front is unstable and for which conditions it is stable. For low coverages the instability will cause the front to break in an array of islands. Assuming that the fastest growing mode of the instability determines t he properties of the array, we make an estimation of the islands sizes and aspect ratios as well as an estimation of the separation length between islands of the array formed when the dominant mechanism for transport of matter is diffusion of particles along the growing front. These estimations are given as functions of the terrace width and coverage. Since these ones are experimentally controllable parameters, our results could be used to tailor the spontaneous formation of quantum nanostructures.

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Colloidal Quantum Nanostructures: Emerging Materials for Display Applications

Angewandte Chemie International Edition ◽

10.1002/anie.201708510 ◽

2018 ◽

Vol 57 (16) ◽

pp. 4274-4295 ◽

Cited By ~ 81

Author(s):

Yossef E. Panfil ◽

Meirav Oded ◽

Uri Banin

Keyword(s):

Quantum Nanostructures

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Mechanisms of Self-Ordering of Quantum Nanostructures Grown on Nonplanar Surfaces

Physical Review Letters ◽

10.1103/physrevlett.81.2962 ◽

1998 ◽

Vol 81 (14) ◽

pp. 2962-2965 ◽

Cited By ~ 126

Author(s):

Giorgio Biasiol ◽

Eli Kapon

Keyword(s):

Quantum Nanostructures

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Dielectric Function of a Quantum-Confined Thin Film with a Modified Pöschel–Teller Potential

Ukrainian Journal of Physics ◽

10.15407/ujpe63.12.1109 ◽

2018 ◽

Vol 63 (12) ◽

pp. 1109 ◽

Cited By ~ 1

Author(s):

Kh. A. Gasanov ◽

J. I. Guseinov ◽

I. I. Abbasov ◽

F. I. Mamedov ◽

D. J. Askerov

Keyword(s):

Dielectric Permittivity ◽

Electron Gas ◽

Two Dimensional ◽

Quantum Nanostructures ◽

Carrier Scattering ◽

Scattering Potential ◽

Quantum Confined ◽

Charge Carrier Scattering ◽

First Time ◽

Analytical Expressions

The spatial and time dispersions of the dielectric permittivity of an electron gas in quasi-two-dimensional quantum nanostructures are studied. The screening of the charge-carrier scattering potential in a quantum-confined film with a modified P¨oschel–Teller potential is considered for the first time. Analytical expressions for the dielectric permittivity are obtained.

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lntersubband Relaxation in Step Quantum Well Structures

VLSI Design ◽

10.1155/1998/17823 ◽

1998 ◽

Vol 8 (1-4) ◽

pp. 289-293

Author(s):

J. P. Sun ◽

H. B. Teng ◽

G. I. Haddad ◽

M. A. Stroscio ◽

G. J. Iafrate

Keyword(s):

Quantum Well ◽

Form Factors ◽

Phonon Energy ◽

Longitudinal Optical Phonon ◽

Relaxation Rates ◽

Phonon Modes ◽

Quantum Well Structures ◽

Bulk Phonon ◽

Interface Phonons ◽

Intersubband Relaxation

Intersubband relaxation due to electron interactions with the localized phonon modes plays an important role for population inversion in quantum well laser structures designed for intersubband lasers operating at mid-infrared to submillimeter wavelengths. In this work, intersubband relaxation rates between subbands in step quantum well structures are evaluated numerically using Fermi's golden rule, in which the localized phonon modes including the asymmetric interface modes, symmetric interface modes, and confined phonon modes and the electron – phonon interaction Hamiltonians are derived based on the macroscopic dielectric continuum model, whereas the electron wave functions are obtained by solving the Schrödinger equation for the heterostructures under investigation. The sum rule for the relationship between the form factors of the various localized phonon modes and the bulk phonon modes is examined and verified for these structures. The intersubband relaxation rates due to electron scattering by the asymmetric interface phonons, symmetric interface phonons, and confined phonons are calculated and compared with the relaxation rates calculated using the bulk phonon modes and the Fröhlich interaction Hamiltonian for step quantum well structures with subband separations of 36 meV and 50meV, corresponding to the bulk longitudinal optical phonon energy and interface phonon energy, respectively. Our results show that for preferential electron relaxation in intersubband laser structures, the effects of the localized phonon modes, especially the interface phonon modes, must be included for optimal design of these structures.

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