Showing papers by "Tolek Tyliszczak published in 1999"
TL;DR: In this article, the average first shell structure has been deduced using simultaneous fitting of all data for alloys grown by molecular beam epitaxy on Si(001) substrates, while imposing physically reasonable constraints.
Abstract: Si and Ge K-edge x-ray absorption fine structure (XAFS) spectra of strained and relaxed ${\mathrm{Si}}_{x}{\mathrm{Ge}}_{1\ensuremath{-}x}$ crystalline alloys grown by molecular beam epitaxy on Si(001) substrates are reported. For alloys with less than 30% Si, fluorescence yield detection is shown to be essential to avoid distortions of the Si K-edge XAFS signal caused by the underlying Ge L-edge XAFS signal from the majority Ge species. The average first shell structure has been deduced using simultaneous fitting of all data for relaxed alloys, while imposing physically reasonable constraints. The Ge-Ge, Ge-Si, and Si-Si first-shell distances are found to vary with composition. The results are compared with other experimental results and theoretical predictions in the literature. Our results are generally consistent with other experimental studies but they differ from recent theoretical predictions based on macroscopic elastic properties in that we observe a different compositional dependence [i.e., slope of $R(x)$ lines] for the Ge-Ge and Si-Si bond lengths. The slope for the Ge-Si bond length composition line was found to be intermediate between that of Si-Si and Ge-Ge.
78 citations
TL;DR: In this paper, the S 2p and S 2s core excitation of SF 6 has been studied using inelastic electron scattering with variable scattering angles and impact energies (momentum transfer (K), 09 K 2 −2 ) and the first Born approximation fails under low impact energy, large scattering angle conditions.
11 citations
TL;DR: In this article, the photofragmentation of carbonyl sulphide following sulphur 1s excitation has been investigated using monochromated synchrotron radiation and ion time-of-flight mass spectroscopy.
10 citations
TL;DR: In this article, first-principles calculations have been used to quantify the Ge(111)MCl surface structure and a stable atop ClMGe monochloride structure was also found in theoretical calculations.
9 citations
TL;DR: In this article, symmetry-dependent P 1s excitation spectra of SPF3 were obtained by performing photoelectron-photoion coincidence measurements with the ion detector oriented both parallel and perpendicular to the electric field vector of the exciting linearly polarized synchrotron radiation.
3 citations
TL;DR: In this article, the structures of monolayers of S and Cl have been studied using synchrotron radiation X-ray absorption fine structure spectroscopy (XAFS).
Abstract: Monolayers of S and Cl have useful passivation properties for group IV and III–V semiconductor surfaces. The structures of Ge(111)–Cl; GaAs(111)–Cl; GaAs(111)A–S, GaAs(111)B–S and GaAs(001)–S monolayer-passivated single crystal semiconductor surfaces have been studied using synchrotron radiation X-ray absorption fine structure spectroscopy (XAFS). The near edge and extended fine structure signals are interpreted using comparisons to multiple scattering XAFS calculations and, in the cases of Ge(111)–Cl and GaAs(111)–Cl, comparison to first-principles calculations. Relationships between the surface structure and the development of improved passivated surfaces are discussed.
1 citations
TL;DR: In this paper, the structure of monolayer-passivated single crystal semiconductor surfaces has been studied using synchrotron radiation X-ray absorption fine structure spectroscopy (XAFS).
Abstract: The structure of monolayer-passivated single crystal semiconductor surfaces has been studied using synchrotron radiation X-ray absorption fine structure spectroscopy (XAFS). The near edge and extended fine structure signals, supported in some cases by first-principles calculations, have been used to investigate Ge(111)-Cl; GaAs(111)-Cl; GaAs(111)A-S, GaAs(111)B-S and GaAs(001)-S. The use of a solid state Ge X-ray fluorescence array detector has led to significant improvements in data quality and thus structural accuracy. The relationship between the derived surface structures and the development of improved passivated surfaces is discussed.