Formation of Ge nanoislands before the completion of a wetting layer in the Ge/Si(111) system

Teys, S. A.; Talochkin, A. B.; Olshanetsky, B.Z.

doi:10.1016/j.jcrysgro.2009.06.021

Cited by 28 publications

(8 citation statements)

References 36 publications

(52 reference statements)

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“…It should be noted, that the results of the calculations are in a good agreement with the experimental data [18,22,30,33,[49][50][51][52][53][54]. For example, for the growth temperature T=500 °C and the germanium deposition rate V=0.03 ML s −1 the proposed theoretical model predicts for the silicon (111) surface the mean lateral size of quantum dots ≈90 nm with the surface density ≈1.2 × 10 9 cm −2 .…”

Section: Resultssupporting

confidence: 75%

Comparative analysis of germanium–silicon quantum dots formation on Si(100), Si(111) and Sn/Si(100) surfaces

2018

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In this paper theoretical modeling of formation and growth of germanium-silicon quantum dots in the method of molecular beam epitaxy (MBE) on different surfaces is carried out. Silicon substrates with crystallographic orientations (100) and (111) are considered. Special attention is paid to the question of growth of quantum dots on the silicon surface covered by tin, since germanium-silicon-tin system is extremely important for contemporary nano-and optoelectronics: for creation of photodetectors, solar cells, light-emitting diodes, and fast-speed transistors. A theoretical approach for modeling growth processes of such semiconductor compounds during the MBE is presented. Both layer-by-layer and island nucleation stages in the Stranski-Krastanow growth mode are described. A change in free energy during transition of atoms from the wetting layer to an island, activation barrier of the nucleation, critical thickness of 2D to 3D transition, as well as surface density and size distribution function of quantum dots in these systems are calculated with the help of the established model. All the theoretical speculations are carried out keeping in mind possible device applications of these materials. In particular, it is theoretically shown that using of the Si(100) surface covered by tin as a substrate for Ge deposition may be very promising for increasing size homogeneity of quantum dot array for possible applications in low-noise selective quantum dot infrared photodetectors.

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Section: Resultssupporting

confidence: 75%

Comparative analysis of germanium–silicon quantum dots formation on Si(100), Si(111) and Sn/Si(100) surfaces

2018

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“…Bare silicon substrates with crystallographic orientations (100) and (111) were historically the first surfaces used for germanium epitaxy. − However, researchers have met the task to reduce the sizes of synthesized islands and to increase their surface density to a maximum extent . Then the surfactant-mediated growth has been studied where the surface of the substrate is capped by surfactant layer, altering its physical properties.…”

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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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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“…3,4 The thickness of the wetting layer depends on the rate of Ge deposition and temperature. 24 When growing at quasi-equilibrium conditions, as it was the case for this work (slow deposition rate 10 −3 -10 −2 BL/min and high temperature, i.e. 300-500 • C), the formation of the Ge wetting layer takes place upon growth and coalescence of neighboring 3-BL thick Ge islands.…”

Section: B Experimental Results and Comparison With Theorymentioning

confidence: 71%

Strain-induced structure transformations on Si(111) and Ge(111) surfaces: A combined density-functional and scanning tunneling microscopy study

Жачук

Teys

Coutinho

2013

The Journal of Chemical Physics

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Si (111) and Ge(111) surface formation energies were calculated using density functional theory for various biaxial strain states ranging from −0.04 to 0.04, and for a wide set of experimentally observed surface reconstructions: 3 × 3, 5 × 5, 7 × 7 dimer-adatom-stacking fault reconstructions and c(2 × 8), 2 × 2 and √ 3 × √ 3 adatoms based surfaces. The calculations are compared with scanning tunneling microscopy data obtained on stepped Si(111) surfaces and on Ge islands grown on a Si(111) substrate. It is shown that the surface structure transformations observed in these strained systems are accounted for by a phase diagram that relates the equilibrium surface structure to the applied strain. The calculated formation energy of the unstrained Si(111)-9 × 9 dimer-adatom-stacking fault surface is reported for the first time and it is higher than corresponding energies of Si(111)-5 × 5 and Si(111)-7 × 7 dimer-adatom-stacking fault surfaces as expected. We predict that the Si(111) surface should adopt a c(2 × 8) reconstruction when tensile strain is above 0.03.

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Formation of Ge nanoislands before the completion of a wetting layer in the Ge/Si(111) system

Cited by 28 publications

References 36 publications

Comparative analysis of germanium–silicon quantum dots formation on Si(100), Si(111) and Sn/Si(100) surfaces

Comparative analysis of germanium–silicon quantum dots formation on Si(100), Si(111) and Sn/Si(100) surfaces

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

Strain-induced structure transformations on Si(111) and Ge(111) surfaces: A combined density-functional and scanning tunneling microscopy study

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