Atomically resolved study of the morphology change of InAs/GaAs quantum dot layers induced by rapid thermal annealing

Keizer, J. G.; Henriques, A. B.; Maia, A. D. B.; Quivy, A. A.; Koenraad, P. M.

doi:10.1063/1.4770371

Cited by 17 publications

(15 citation statements)

References 26 publications

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“…In such a way, the overall shape of the quantum dot, the atomic structure of the wetting layers and dot, and the presence and effect of doping atoms can be studied. The solid that contains the self-assembled quantum dots can be cleaved under ultrahigh-vacuum conditions, enabling cross-sectional microscopy and energy-level spectroscopy (refs , , , , − , − , − , , and − ). Recently, cross-sectional microscopy has been combined with atom probe tomography, which allows one to make detailed cross sections of the atomic structure of the quantum dot combined with tunneling spectroscopy.…”

Section: Colloidal Nanocrystals Of Semiconductor Compounds: Scientifi...mentioning

confidence: 99%

Scanning probe microscopy and spectroscopy of colloidal semiconductor nanocrystals and assembled structures

2016

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Colloidal semiconductor nanocrystals become increasingly important in materials science and technology, due to their optoelectronic properties that are tunable by size. The measurement and understanding of their energy levels is key to scientific and technological progress. Here we review how the confined electronic orbitals and related energy levels of individual semiconductor quantum dots have been measured by means of scanning tunneling microscopy and spectroscopy. These techniques were originally developed for flat conducting surfaces, but they have been adapted to investigate the atomic and electronic structure of semiconductor quantum dots. We compare the results obtained on colloidal quantum dots with those on comparable solid-state ones. We also compare the results obtained with scanning tunneling spectroscopy with those of optical spectroscopy. The first three sections provide an introduction to colloidal quantum dots, and a theoretical basis to be able to understand tunneling spectroscopy on dots attached to a conducting surface. In sections 4 and 5 , we review the work performed on lead-chalcogenide nanocrystals and on colloidal quantum dots and rods of II-VI compounds, respectively. In section 6 , we deal with colloidal III-V nanocrystals and compare the results with their self-assembled counter parts. In section 7 , we review the work on other types of semiconductor quantum dots, especially on Si and Ge nanocrystals.

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Section: Colloidal Nanocrystals Of Semiconductor Compounds: Scientifi...mentioning

confidence: 99%

Scanning probe microscopy and spectroscopy of colloidal semiconductor nanocrystals and assembled structures

2016

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“…In QDs (see Figure a–d) the three‐dimensional confinement of charge carriers in a small volume of typically a few nanometers [ 99 ] leads to quantized energy levels in the valence and conduction band, resulting in discrete atom‐like transitions. The lowest energy levels are referred to as s‐shell (in analogy to atoms) and can be approximated as a two‐level system (cf.…”

Section: Quantum Dot Based Quantum Light Sourcesmentioning

confidence: 99%

Quantum Communication Using Semiconductor Quantum Dots

et al. 2022

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Worldwide, enormous efforts are directed toward the development of the so-called quantum internet. Turning this long-sought-after dream into reality is a great challenge that will require breakthroughs in quantum communication and computing. To establish a global, quantum-secured communication infrastructure, photonic quantum technologies will doubtlessly play a major role, by providing and interfacing essential quantum resources, for example, flying-and stationary qubits or quantum memories. Over the last decade, significant progress has been made in the engineering of on-demand quantum light sources based on semiconductor quantum dots, which enable the generation of close-to-ideal single-and entangled-photon states, useful for applications in quantum information processing. This review focuses on implementations of, and building blocks for, quantum communication using quantum-light sources based on epitaxial semiconductor quantum dots. After reviewing the main notions of quantum communication and introducing the devices used for single-photon and entangled-photon generation, an overview of experimental implementations of quantum key distribution protocols using quantum dot based quantum light sources is provided. Furthermore, recent progress toward quantum-secured communication networks as well as building blocks thereof is summarized. The article closes with an outlook, discussing future perspectives in the field and identifying the main challenges to be solved.

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“…X-STM can directly visualize the atomic structure of the surface and so precisely determining the size and shape of the embedded QDs. The structural and compositional changes after overgrowth such as intermixing, segregation and morphological changes in QDs can also be studied by X-STM [ 50 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 ]. The cleaving of the sample produces an outward relaxation due to the compressively strained QDs and this can be experimentally measured by X-STM.…”

Section: Characterization Techniquesmentioning

confidence: 99%

Atomic-Scale Characterization of Droplet Epitaxy Quantum Dots

Gajjela

Koenraad

2021

Nanomaterials

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The fundamental understanding of quantum dot (QD) growth mechanism is essential to improve QD based optoelectronic devices. The size, shape, composition, and density of the QDs strongly influence the optoelectronic properties of the QDs. In this article, we present a detailed review on atomic-scale characterization of droplet epitaxy quantum dots by cross-sectional scanning tunneling microscopy (X-STM) and atom probe tomography (APT). We will discuss both strain-free GaAs/AlGaAs QDs and strained InAs/InP QDs grown by droplet epitaxy. The effects of various growth conditions on morphology and composition are presented. The efficiency of methods such as flushing technique is shown by comparing with conventional droplet epitaxy QDs to further gain control over QD height. A detailed characterization of etch pits in both QD systems is provided by X-STM and APT. This review presents an overview of detailed structural and compositional analysis that have assisted in improving the fabrication of QD based optoelectronic devices grown by droplet epitaxy.

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Atomically resolved study of the morphology change of InAs/GaAs quantum dot layers induced by rapid thermal annealing

Abstract: Koenraad, P. M. (2012). Atomically resolved study of the morphology change of InAs/GaAs quantum dot layers induced by rapid thermal annealing. Applied

Cited by 17 publications

References 26 publications

Scanning probe microscopy and spectroscopy of colloidal semiconductor nanocrystals and assembled structures

Scanning probe microscopy and spectroscopy of colloidal semiconductor nanocrystals and assembled structures

Quantum Communication Using Semiconductor Quantum Dots

Atomic-Scale Characterization of Droplet Epitaxy Quantum Dots

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