Short-range order structures of self-assembled Ge quantum dots probed by multiple-scattering extended x-ray absorption fine structure

Sun, Zhihu; Wei, Shiqiang; Kolobov, Alexander V.; Ōyanagi, H.; Βrunner, Karl

doi:10.1103/physrevb.71.245334

Cited by 17 publications

(17 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Their slope represents the average height of islands following the line. 55 The different contribution of these scattering mechanisms to the spectrum obtained from the Ge-in-Si and Ge bulk reference samples are displayed in Fig. 2.…”

Section: B Gesi Coordination Numbersmentioning

confidence: 99%

GeSi intermixing in Ge nanostructures on Si(111): An XAFS versus STM study

et al. 2007

View full text Add to dashboard Cite

We report a detailed investigation of interdiffusion processes that occur during the growth of germanium nanostructures on the (111)-oriented surface of silicon. In particular, X-ray Absorption Fine Structure (XAFS) measurements performed ex situ show that a Ge(1-x)Si(x) alloy forms during deposition, with average composition x varying between 0.25 and 0.50, depending on substrate temperature and total coverage. By fitting the Si nearest-neighbor numbers around Ge as a function of the deposited thickness with a simple model, the effective vertical composition profile in the growth direction has been estimated. The latter has been described with a static effective diffusion length of (10.0 +/- 1.5) nm at 530 degrees C and (5 +/- 1) nm at 450 degrees C, which is interpreted as the dominance of surface transport processes in the intermixing dynamics. The analysis of the data on Ge-Ge bond length indicates a decrease of the Ge-Ge atomic distances with increasing Ge fraction, confirming previous theoretical predictions for strained epilayers. The XAFS results are compared to morphological information obtained by scanning tunneling microscopy investigations carried out in situ, yielding a satisfactory description for the epitaxy of this system

show abstract

Section: B Gesi Coordination Numbersmentioning

confidence: 99%

GeSi intermixing in Ge nanostructures on Si(111): An XAFS versus STM study

et al. 2007

View full text Add to dashboard Cite

show abstract

“…A simultaneous determination of their strain and composition is of interest. Sun et al [65] first used the EXAFS method to study the local structures around Ge atoms in the first three coordination shells for self-assembled the Ge QDs grown at 510°C and then capped by Si at different temperatures (300 and 510°C). The authors first performed a preliminary multiple-scattering fitting on the data of crystalline Ge using all 10 scattering paths in the The schematic surface strain in 1-and 2-ML Ge on Si(001).…”

Section: Science China Materialsmentioning

confidence: 99%

X-ray absorption fine structure spectroscopy in nanomaterials

et al. 2015

Self Cite

View full text Add to dashboard Cite

X-ray absorption fine structure (XAFS) spectroscopy has been widely used for decades in a wide range of scientific fields, including physics, chemistry, biology, materials sciences, environmental sciences, etc. This review article is devoted to the applications of XAFS in nanomaterials. The basic principles of XAFS are briefly described from the view point of practical application, including its theory, data analysis and experiments. Using selected examples from recent literatures, the power of XAFS in determination of local atomic/electronic structures is illustrated for various nanomaterials, covering metal and semiconductor nanoparticles, catalysts, core/shell structures, ultrathin nanosheets, and so on. The utilization of time-resolved XAFS technique is also briefly introduced, for in-situ probing the nucleation/growth processes of nanomaterials and identifying reaction intermediates of nanostructured catalysts under operando conditions.

show abstract

“…In the case of the bulk crystalline Ge, the fitting model to describe the signal in the R-space window from 1 to 4.7 Å requires inclusion of three single-scattering (S) paths (1, 3 and 5 in Table 3), two double-scattering (DS) paths (7 and 8) and one triple-scattering path (10; Sun et al, 2005). The single-and multiple-scattering paths indicated in Table 3 are visualized in Fig.…”

Section: X-ray Absorption Spectroscopymentioning

confidence: 99%

Investigation of indirect structural and chemical parameters of GeSi nanoparticles in a silica matrix by combined synchrotron radiation techniques

et al. 2011

View full text Add to dashboard Cite

The formation of GeSi nanoparticles on an SiO 2 matrix is studied here by synchrotron-based techniques. The shape, average diameter and size dispersion were obtained from grazing-incidence small-angle X-ray scattering data. X-ray diffraction measurements were used to obtain crystallite sizes and composition via resonant (anomalous) measurements. By using these techniques as input for extended X-ray absorption fine structure analysis, the local composition surrounding the Ge atoms is investigated. Although the results for each of the methods above are commonly analyzed separately, the combination of such techniques leads to an improved understanding of nanoparticle structural and chemical properties. Crucial indirect parameters that cannot be quantified by other means are accessed in this work, such as local strain, the possibility of forming core-shell structures, the fraction of Ge atoms diluted in the matrix (not forming nanoparticles), the amorphous and crystalline Ge fractions, and the relative population of nanoparticles with single and multiple crystalline domains.

show abstract

Short-range order structures of self-assembled Ge quantum dots probed by multiple-scattering extended x-ray absorption fine structure

Cited by 17 publications

References 54 publications

GeSi intermixing in Ge nanostructures on Si(111): An XAFS versus STM study

GeSi intermixing in Ge nanostructures on Si(111): An XAFS versus STM study

X-ray absorption fine structure spectroscopy in nanomaterials

Investigation of indirect structural and chemical parameters of GeSi nanoparticles in a silica matrix by combined synchrotron radiation techniques

Contact Info

Product

Resources

About