Lattice contraction in nanosized silicon particles produced by laser pyrolysis of silane

Hofmeister, H.; Huisken, F.; Kohn, Bernhard

doi:10.1007/978-3-642-88188-6_26

Cited by 13 publications

(13 citation statements)

References 19 publications

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“…The average bond length and coordination number for each region are calculated and presented in Table . We find that, for all simulated particles, the average bond length of the core region indicates a contraction of approximately 2% relative to bulk Si, in agreement with reports of a decrease in lattice parameter with decreasing nanoparticle size. − Furthermore, for all samples, the average bond length of the surface region is greater than that found in the core, reflective of a low-density disordered surface, with a higher concentration of under-coordinated atoms.…”

supporting

confidence: 87%

Probing Dopant Locations in Silicon Nanocrystals via High Energy X-ray Diffraction and Reverse Monte Carlo Simulation

2019

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Understanding the locations of dopant atoms in ensembles of nanocrystals is crucial to controlling the dopants’ function. While electron microscopy and atom probe tomography methods allow investigation of dopant location for small numbers of nanocrystals, assessing large ensembles has remained a challenge. Here, we are using high energy X-ray diffraction (HE-XRD) and structure reconstruction via reverse Monte Carlo simulation to characterize nanocrystal structure and dopant locations in ensembles of highly boron and phosphorus doped silicon nanocrystals (Si NCs). These plasma-synthesized NCs are a particularly intriguing test system for such an investigation, as elemental analysis suggests that Si NCs can be “hyperdoped” beyond the thermodynamic solubility limit in bulk silicon. Yet, free carrier densities derived from local surface plasmon resonances suggest that only a fraction of dopants are active. We demonstrate that the structural characteristics garnered from HE-XRD and structure reconstruction elucidate dopant location and doping efficacy for doped Si NCs from an atomic-scale perspective.

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supporting

confidence: 87%

Probing Dopant Locations in Silicon Nanocrystals via High Energy X-ray Diffraction and Reverse Monte Carlo Simulation

2019

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“…The origin of this expansion is because of the larger molar volume of SiO 2 compared to Si. A volume expansion of the unoxidized region of Si nanomaterials has been reported previously, in both experimental 41 and theoretical 24 studies of surface oxidation. In the few nanometer scale, the inner core of the Si particle or Si NW cannot sustain the volume expansion of the surface oxide layer, and it becomes energetically more favorable for the inner Si core atoms to deform to release the stress of the surface oxide layer.…”

Section: ■ Results and Discussionsupporting

confidence: 56%

Indirect-to-Direct Band Gap Transition of Si Nanosheets: Effect of Biaxial Strain

et al. 2018

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The effect of biaxial strain on the band structure of two-dimensional silicon nanosheets (Si NSs) with ( 111), (110), and (001) exposed surfaces was investigated by means of density functional theory calculations. For all the considered Si NSs, an indirect-to-direct band gap transition occurs as the lateral dimensions of Si NSs increase; that is, increasing lateral biaxial strain from compressive to tensile always enhances the direct band gap characteristics. Further analysis revealed the mechanism of the transition which is caused by preferential shifts of the conduction band edge at a specific k-point because of their bond characteristics. Our results explain a photoluminescence result of the ( 111) Si NSs [U. Kim et al., ACS Nano 2011, 5, 2176−2181] in terms of the plausible tensile strain imposed in the unoxidized inner layer by surface oxidation.

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“…The oxide shell thickness could be correlated linearly to the cluster diameter. The smallest clusters of 6 nm in diameter had an oxide shell with a thickness of 0.81 nm, whilst the largest particles had a diameter of 34 nm had a 3 nm thick oxide shell (Hofmeister et al, 1999). The HRTEM images showed that the nanoparticles had a crystalline core.…”

Section: Red-orange Luminescencementioning

confidence: 97%

“…An exemption from these principles is shown in the work of Laguna and co-workers, however, who deposited silicon clusters produced by pyrolysis of silane onto holey carbon films. High resolution transmission electron images clearly shows nanoparticles with lattice planes surrounded by an amorphous oxide shell (Hofmeister et al, 1999;Laguna et al, 1999).…”

Section: Geometric Structurementioning

confidence: 99%

Fluorescent silicon clusters and nanoparticles

Haeften¹

2017

Silicon Nanomaterials Sourcebook

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Clusters, consisting of a small number of atoms, have been in the focus of physical and chemical research for several decades. They often show dramatic size effects. The addition of a single atoms can change their properties rather abruptly because of, for example, the discreteness of shell filling (Knight et al., 1984) or sphere-packing effects (Echt et al., 1981). When clusters become larger and reach the nanometre scale, other effects are observed, such as quantum confinement; The intense red fluorescence observed for nanostructured silicon (Canham, 1990;Cullis and Canham, 1991;Wilson et al., 1993;Lockwood, 1994;Cullis et al., 1997) is a popular and frequently cited example of this effect.The discovery of fluorescent nanoscale silicon at room temperature by Canham (Canham, 1990) increased the already quite intense research into silicon clusters where n is the principal quantum number,h the reduced Planck (or Dirac) constant and m e the electron mass. The quantum number, n, is indexed from n = 1, and the energy difference E(n = 2) and E(n = 1) would be equivalent to the fluorescence energy from the first excited state to the ground state.The analogy of the one-dimensional model can be straightforwardly extended

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Lattice contraction in nanosized silicon particles produced by laser pyrolysis of silane

Cited by 13 publications

References 19 publications

Probing Dopant Locations in Silicon Nanocrystals via High Energy X-ray Diffraction and Reverse Monte Carlo Simulation

Probing Dopant Locations in Silicon Nanocrystals via High Energy X-ray Diffraction and Reverse Monte Carlo Simulation

Indirect-to-Direct Band Gap Transition of Si Nanosheets: Effect of Biaxial Strain

Fluorescent silicon clusters and nanoparticles

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