Growth and structure of Ge nanoislands on an atomically clean silicon oxide surface

Nikiforov, A. I.; Ulyanov, Vladimir V.; Pchelyakov, O. P.; Teys, S. A.; Гутаковский, А. К.

doi:10.1134/1.1641926

Cited by 15 publications

(13 citation statements)

References 7 publications

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“…For calculations of characteristics of germanium quantum dots array on the surface of silicon oxide the following values of parameters of the model were used: 23,38,46,53 In order to find the equilibrium thickness of the 2D layer h eq in the case of quantum dots growth in the Ge/SiO 2 /Si system eq 12 was used. In accordance with Muller−Kern criterion 52,54 for the thicknesses of the 2D layer h < h eq layer-by-layer growth is realized.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Formation of germanium islands on the silica surface is shown schematically in Figure 1. 23,38,40,41 In this work, for the first time kinetic model of nucleation and growth of 3D islands by Volmer−Weber mechanism based on Zeldovich's general nucleation theory is proposed. The developed model allows one to evaluate not only equilibrium values of system with quantum dots (their average size and surface density), but also principally nonequilibrium parameters such as islands nucleation rate, size distribution function and its time evolution.…”

Section: ■ Introductionmentioning

confidence: 99%

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Evolution of Epitaxial Quantum Dots Formed by Volmer–Weber Growth Mechanism

Lozovoy

Коханенко

Dirko

et al. 2019

Crystal Growth & Design

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Germanium/silicon systems are among the most promising materials for development of current semiconductor electronics and photonics. Structures with germanium quantum dots on silicon are very interesting from the point of view of the creation of fast-speed transistors, photodetectors, and solar cells. The basic method of the synthesis of nanoislands is their self-organization in the process of molecular beam epitaxy. It was experimentally shown that ultrahigh surface densities (up to 1012–1013 cm–2) of nanometer-sized clusters may be achieved by deposition of germanium on oxidized rather than bare silicon surfaces. Nevertheless, this system with a thin layer of silicon oxide is poorly investigated. In this work, fundamental peculiarities of epitaxial formation and growth of quantum dots by the Volmer–Weber growth mechanism are considered. A kinetic model of nucleation and growth of three-dimensional islands by the Volmer–Weber mechanism based on the general nucleation theory is proposed for the first time. The developed model allows one to evaluate not only equilibrium values of a system with quantum dots (their average size and surface density), but also principally nonequilibrium parameters such as islands nucleation rate, size distribution function, and its time evolution. Dependencies of mean lateral size and surface density of Volmer–Weber quantum dots on the conditions of their synthesis (growth temperature and deposition rate) are obtained. The results of numerical simulations of Volmer–Weber growth for the Ge/SiO2/Si system show very good agreement with experimental data. The proposed theoretical model may be easily applied for other material systems where growth of islands by the Volmer–Weber mechanism is realized.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Evolution of Epitaxial Quantum Dots Formed by Volmer–Weber Growth Mechanism

Lozovoy

Коханенко

Dirko

et al. 2019

Crystal Growth & Design

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“…7 In turn, statistical fluctuations of the QD size is a main source of inhomogeneous broadening of the DOS. For Ge/ Si͑001͒ QD's, several approaches have been exploited to tune the uniformity of the Ge island sizes and shapes, such as manipulating the substrate temperature 8,9 and the deposition sequence, 10 vertical ordering in QD multilayers, [11][12][13] surfactant-mediated growth, 14,15 deposition on vicinal, 16 and oxidized 17 surfaces, ion-beam stimulated growth. 18 Despite some technological progress any information on how these approaches affect the energy spectrum of carriers confined in an ensemble of QD's is still missing.…”

Section: Introductionmentioning

confidence: 99%

Effect of pulsed laser action on hole-energy spectrum ofGe∕Siself-assembled quantum dots

et al. 2005

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Space-charge spectroscopy has been used to study the hole energy spectrum of an array of Ge quantum dots ͑QD's͒ coherently embedded in a Si matrix and subjected to a ruby laser ͑ = 694 nm͒ nanosecond irradiation ex situ. The laser energy density in a single pulse was near the melting threshold of the Si surface. The number of laser pulses was varied from 1 to 10, and the duration of each pulse was 80 ns. From the capacitance-voltage characteristics, temperature-and frequency-dependent admittance measurements, the energies of holes confined in Ge QD's were determined. The pulsed laser annealing was found to result in a deepening of the hole energy level relative to the bulk Si valence band edge and in a decrease of the hole energy dispersion. After the treatment with ten laser pulses, the spread of the hole energies due to varying sizes of the QD's within the ensemble was reduced by a factor of about 2. The obtained results give evidence for a substantial reduction of the QD's size dispersion and for a narrowing distribution of the hole energy levels stimulated by nanosecond laser irradiation. A possible explanation of the improved uniformity of QD's sizes involves dissolving small size Ge QD's in a Si matrix by pulsed laser melting of the Ge nanoclusters and their subsequent intermixing with surrounding solid Si.

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“…At the film not thicker than five monolayers (ML), the islands are less than 10 nm in base diameter and have the density higher than 2 × 10 12 cm −2 (Ref. [39]) ( Fig. 2(a)).…”

Section: Size and Density Of Self-assembled Quantum Dotsmentioning

confidence: 99%

“…This approach uses Volmer-Weber growth mode and allows to form Ge nanoclusters which exhibit an epitaxial relationship with the underlying silicon substrate and reside on bare Si region similar to the case of Stranskii-Krastanov islands. 39 The Ge islands have a hemispherical shape with a base diameter of 5 8 ± 0 5 nm and a height of about 3-4 nm. The apex of the dots is oriented along the growth direction.…”

Section: Stark Effect In Ge/sio X /Si Quantum Dotsmentioning

confidence: 99%

Germanium Self-Assembled Quantum Dots in Silicon for Nano- and Optoelectronics

Yakimov¹,

Двуреченский²,

Никифоров³

2006

Journal of Nanoelectronics and Optoelectronics

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The scope of this article is to review the formation mechanisms, variety of electronic and optical phenomena, as well as possible device-oriented applications, in Ge/Si self-assembled quantum dots that have been synthesized by molecular-beam heteroepitaxy. A difference of this review from the other existing works on physics of Ge/Si nanostructures is that we will focus on the fundamental aspects and device applications of the dots whose size is extremely small (∼10 nm) and the electronic states resemble certainly those of an atom even at room temperature.

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Growth and structure of Ge nanoislands on an atomically clean silicon oxide surface

Cited by 15 publications

References 7 publications

Evolution of Epitaxial Quantum Dots Formed by Volmer–Weber Growth Mechanism

Evolution of Epitaxial Quantum Dots Formed by Volmer–Weber Growth Mechanism

Effect of pulsed laser action on hole-energy spectrum ofGe∕Siself-assembled quantum dots

Germanium Self-Assembled Quantum Dots in Silicon for Nano- and Optoelectronics

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