Formation of Ge-Sn nanodots on Si(100) surfaces by molecular beam epitaxy

Mashanov, V. I.; Ulyanov, Vladimir V.; Тимофеев, В. А.; Nikiforov, A. I.; Pchelyakov, O. P.; Yu, Ing-Song; Cheng, Hung-Hsiang

doi:10.1186/1556-276x-6-85

Cited by 16 publications

(7 citation statements)

References 13 publications

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“…Then the surfactant-mediated growth has been studied where the surface of the substrate is capped by surfactant layer, altering its physical properties. Various materials were used as a surfactant, such as antimony Sb, − bismuth Bi, tin Sn, − and some others. For all these systems, a so-called Stranski–Krastanow growth mode is typical.…”

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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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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“…For GeSn ND epitaxy, it has also been reported that GeSn NDs are formed by low-temperature MBE growth (250 °C-400 °C), and the authors assumed low-temperature growth was made possible by the surfactant effect of Sn. 22) In contrast, because our method for forming GeSn NDs is by annealing amorphous GeSn layers, the mechanism of the low-temperature formation of NDs cannot be explained by only the enhancement of adatoms but should be explained by considering the migration of atoms in the amorphous alloy layers. Because enhancement of migration in amorphous Table II.…”

Section: Discussionmentioning

confidence: 96%

“…14,15) A solution to these problems is to form GeSn QDs under low temperature. 21) Some reports on the formation of GeSn QDs and NDs and theoretical studies have been made in recent years, [22][23][24][25] and electroluminescence (10 K) in the optical communication wavelength range has also been reported. 26) However, further progress is needed to realize light-emitting devices.…”

Section: Introductionmentioning

confidence: 99%

Low-temperature formation of GeSn nanodots by Sn mediation

Okamoto

Takita

Tsushima

et al. 2019

Jpn. J. Appl. Phys.

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GeSn is expected as a light-emitting material in Si photonics because a direct-bandgap nature appears with Sn composition above 10%. However, the emission wavelength of GeSn is in the mid-IR range. Thus, GeSn nanodots (NDs) are needed for telecom-wavelength emission. In this paper, we propose a formation method for GeSn NDs with Sn mediation. This process consists of low-temperature deposition of Sn and GeSn by vacuum evaporation and subsequent low-temperature annealing. Crystalline GeSn NDs with high density and high Sn content (more than 10%) have been successfully formed without metallic Sn precipitation or segregation of Sn on the dot surface. The possible formation mechanism of Sn-mediated GeSn NDs is also discussed.

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“…There are also a lot of experimental works devoted to the growth of GeSi 2D layers and 3D islands, including the case of the presence of tin, as these systems are very perspective for device applications [24][25][26][27][28][29][30][31][32]. But there is a lack of theoretical investigations capable to predict values of the critical thickness of transition from 2D to 3D growth, mean lateral size, and surface density of quantum dots in the whole range of temperatures, deposition rates, and compositions for these material systems.…”

Section: Introductionmentioning

confidence: 99%

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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Formation of Ge-Sn nanodots on Si(100) surfaces by molecular beam epitaxy

Cited by 16 publications

References 13 publications

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

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

Low-temperature formation of GeSn nanodots by Sn mediation

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

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