Electronic structure and interfacial properties of Ge nanoclusters embedded in amorphous silica

Du, Jincheng; Kroll, Peter

doi:10.1016/j.jnoncrysol.2010.03.040

Cited by 11 publications

(5 citation statements)

References 30 publications

(51 reference statements)

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“…( 2 ) gives ≈ 0.8 J/m 2 . This value is consistent with the literature data, according to which the Ge/SiO 2 interface energy is larger than the SiO 2 surface energy 73 , 74 . In the structures with such relationships between and , the size of the base of particles should be smaller than their lateral dimension.…”

Section: Resultssupporting

confidence: 93%

Dewetting behavior of Ge layers on SiO2 under annealing

Shklyaev

Латышев

2020

Sci Rep

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the solid-state dewetting phenomenon in Ge layers on Sio 2 is investigated as a function of layer thickness d Ge (from 10 to 86 nm) and annealing temperature. The dewetting is initiated at about 580-700 °C, depending on d Ge , through the appearance of surface undulation leading to the particle formation and the rupture of Ge layers by narrow channels or rounded holes in the layers with the thicknesses of 10-60 and 86 nm, respectively. The channel widths are significantly narrower than the distance between the particles that causes the formation of thinned Ge layer areas between particles at the middle dewetting stage. the thinned areas are then agglomerated into particles of smaller sizes, leading to the bimodal distributions of the Ge particles which are different in shape and size. The existence of a maximum in the particle pair correlation functions, along with the quadratic dependence of the corresponding particle spacing on d Ge , may indicate the spinodal mechanism of the dewetting in the case of relatively thin Ge layers. Despite the fact that the particle shape, during the solid-state dewetting, is not thermodynamically equilibrium, the use of the Young's equation and contact angles allows us to estimate the particle/substrate interface energy.

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Section: Resultssupporting

confidence: 93%

Dewetting behavior of Ge layers on SiO2 under annealing

Shklyaev

Латышев

2020

Sci Rep

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“…In the literature, DFT has been used to investigate different glassy systems containing low hundreds of atoms (<400) to address problems such as the structural evolution of germanium melts, embedded clusters in silica, bioactivity mechanism of soda-lime phosphosilicate glasses, interface of silicon surfaces with water, densification of silica, molten glass structures, and nanocomposite materials for solar energy collection . These studies used B3LYP, PBE0, and PW91 functionals that have shown good predictions for the structure, compositional changes, and band gap.…”

Section: Introductionmentioning

confidence: 99%

Adhesion of Organic Molecules on Silica Surfaces: A Density Functional Theory Study

et al. 2016

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Understanding the interface between organic and inorganic materials presents many challenges due to the complex chemistries involved. Modeling and experimental work have elucidated only a few facets of the physical and chemical nature of the adhesion between such surfaces. In this work, we use density functional theory to understand the adhesion between five different inorganic crystal surfaces (two-dimensional silica, both sides of kaolinite, hydroxylated quartz, hydroxylated albite) with five different organic molecules (benzene, phenol, phthalimide, N-phenylmaleimide, diphenyl ether). In the analysis, we explore the binding motifs that constitute parts of a polyimide monomer and examine their interactions with increasingly complex crystal surfaces. Comparing these systems, we elucidate the key factors (such as electrostatic interactions, hydrogen bond formation, and cation effects) that affect adhesion of organics on inorganic surfaces. It is found that the presence of cations and the availability of the oxygen species, in either the organic or inorganic layers, allows for increased hydrogen bonding. The most significant contribution to adhesion is from the rearrangement of surface electrostatic interactions. These factors can be used to optimize adhesion by decomposing both the organic and inorganic materials into the constituent interactions and help design improved interfacial properties.

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“…We use the term nanodot to emphasise their amorphous character, which distinguishes it from nanocrystals (NCs) that almost exhibit the crystal structure of the bulk material. The atomic models are generated from the diamond structure of Si, and disorder within the quantum dot region is generated using a simple bondswitching method [16]. Structural, electronic and optical properties are calculated using ab initio methods including spin-orbit and quasiparticle effects.…”

Section: Introductionmentioning

confidence: 99%

Amorphous Ge quantum dots embedded in crystalline Si:ab initioresults

Laubscher

Küfner

Kroll

et al. 2015

J. Phys.: Condens. Matter

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We study amorphous Ge quantum dots embedded in a crystalline Si matrix through structure modeling and simulation using ab initio density functional theory including spin-orbit interaction and quasiparticle effects. Three models are generated by replacing a spherical region within diamond Si by Ge atoms and creating a disordered bond network with appropriate density inside the Ge quantum dot. After total-energy optimisations of the atomic geometry we compute the electronic and optical properties. We find three major effects: (i) the resulting nanostructures adopt a type-I heterostructure character; (ii) the lowest optical transitions occur only within the Ge quantum dots, and do not involve or cross the Ge-Si interface. (iii) for larger amorphous Ge quantum dots, with diameters of about 2.0 and 2.7 nm, absorption peaks appear in the mid-infrared spectral region. These are promising candidates for intense luminescence at photon energies below the gap energy of bulk Ge.

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Electronic structure and interfacial properties of Ge nanoclusters embedded in amorphous silica

Cited by 11 publications

References 30 publications

Dewetting behavior of Ge layers on SiO2 under annealing

Dewetting behavior of Ge layers on SiO2 under annealing

Adhesion of Organic Molecules on Silica Surfaces: A Density Functional Theory Study

Amorphous Ge quantum dots embedded in crystalline Si:ab initioresults

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