X-ray photoelectron study of Ca, Sr and Ba ion chemical states in high-Tc superconductors

Teterin, Yu. A.; Sosulnikov, M.I.

doi:10.1016/0921-4534(93)90594-g

Cited by 20 publications

(12 citation statements)

References 34 publications

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“…Depth profiles were obtained by alternating sputter etching rastered over a 3 3 mm 2 area (with a 4 kV argon ion gun), and XPS analysis. BE data were calibrated on C1s at 285 eV [34,35]. The sputtering rate of LaF 3 films was estimated on the basis of standard LaF 3 films, the thicknesses of which were determined by SEM cross sections.…”

Section: Methodsmentioning

confidence: 99%

In-situ Synthesis of the Anhydrous La(hfac)3 Precursor: A Viable Route to the MOCVD of LaF3

Condorelli

Gennaro

Fragalá³

2001

Chem. Vap. Deposition

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The anhydrous La(hfac) 3 precursor was obtained in situ by a vapor±solid reaction between hexafluoroacetylactonate (Hhfac) and La 2 O 3 powder in the source reservoir of a metal±organic chemical vapor deposition (MOCVD) reactor. Fourier transform infrared spectroscopy (FTIR) in-situ measurements were used to identify the nature of the precursor in the gas phase. Clean LaF 3 films (60±260 nm thick) were deposited on SiO 2 /Si substrates in both Ar and Ar/O 2 environments. They were characterized by grazing incidence X-ray diffraction, (GIXRD), X-ray photoelectron spectroscopy (XPS) depth profiles, scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) analysis. Very thin (<15 nm) films were also deposited in order to investigate the nucleation and growth processes. Deposited films were found to consist of islands grown on the silicon substrate. The surface coverage depends on the sublimation and substrate temperatures, as well as on the nature of the carrier/reacting gas.

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Section: Methodsmentioning

confidence: 99%

In-situ Synthesis of the Anhydrous La(hfac)3 Precursor: A Viable Route to the MOCVD of LaF3

Condorelli

Gennaro

Fragalá³

2001

Chem. Vap. Deposition

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“…Depth profiles were obtained by alternating sputter etching rastered over a 3 mm 3 mm area, (with a 4 kV argon ion gun) and XPS analysis. BE data were calibrated on C 1s at 285 eV [41,42]. The sputtering rate was estimated on standard YF 3 films the thicknesses of which were determined by SEM cross-sections.…”

Section: Full Papermentioning

confidence: 99%

MOCVD of YF₃ and Y_1–_xEr_xF₃ Thin Films from Precursors Synthesized In Situ

Condorelli¹,

Anastasi²,

Fragalá³

2005

Chemical Vapor Deposition

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RE(hfac) 3 precursors (RE = Y, Er and Hhfac=1,1,1,5,5,5-hexafluoroacetylacetonate) have been obtained in-situ in a metalorganic (MO) CVD reactor by vapor-solid reaction between Hhfac and powders of suitable mixtures of RE 2 O 3 oxides. YF 3 and Y 1±x Er x F 3 (x » 0.2) ultra-thin films have been deposited over glass substrates under Ar/O 2 environments. Fourier-transform infrared (FTIR) in-situ measurements have been used to identify the nature of the precursor species in the gas phase, as well as to investigate decomposition mechanisms which accompany the film growth. Deposition involves the breakdown of the metal± ligand bond, thus leading to free Hhfac ligands and fluorinated ketones. Films have been characterized by energy dispersive X-ray (EDX) microanalysis, grazing incidence X-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM).

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“…Employment of high spectral resolution and good quality crystals reveals distinctly separated features in contrast to earlier data. 45,49,50 The dominant lines at low binding energy clearly shift to lower binding energies with increasing oxygen concentration. The energy shift observed for the Ba core level lines is significantly larger than that observed in the Y 3d spectra shown in Fig.…”

Section: A Yba2cu3o6+xmentioning

confidence: 98%

“…Previously, XPS studies on the surface of YBa 2 Cu 3 O 6+x have been published for single crystals, 38,45,46 polycrystalline samples, 47,48 and thin films. 49,50 In this context we also mention scanning tunneling microscopy (STM) 51,52,53,54 studies on single crystals. More recently, information on the surface of cleaved YBa 2 Cu 3 O 6+x single crystals have been also derived from Angle-Resolve Photoemission Spectroscopy (ARPES) studies.…”

Section: Introductionmentioning

confidence: 99%

Doping dependence of the chemical potential and surface electronic structure in YBa2Cu3O6+x and La2-xSrxCuO4 using hard x-ray photoemission spectroscopy

Maiti,

Fink,

de Jong

et al. 2009

Preprint

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The electronic structure of YBa2Cu3O6+x and La2−xSrxCuO4 for various values of x has been investigated using hard x-ray photoemission spectroscopy. The experimental results establish that the cleaving of YBa2Cu3O6+x compounds occurs predominantly in the BaCuO3 complex leading to charged surfaces at higher x and to uncharged surfaces at lower x values. The bulk component of the core level spectra exhibits a shift in binding energy as a function of x, from which a shift of the chemical potential as a function of hole concentration in the CuO2 layers could be derived. The doping dependence of the chemical potential across the transition from a Mott-Hubbard insulator to a Fermi-liquid-like metal is very different in these two series of compounds. In agreement with previous studies in the literature the chemical potential shift in La2−xSrxCuO4 is close to zero for small hole concentrations. In YBa2Cu3O6+x, similar to all other doped cuprates studied so far, a strong shift of the chemical potential at low hole doping is detected. However, the results for the inverse charge susceptibility at small x shows a large variation between different doped cuprates. The results are discussed in view of various theoretical models. None of these models turns out to be satisfactory.

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X-ray photoelectron study of Ca, Sr and Ba ion chemical states in high-Tc superconductors

Cited by 20 publications

References 34 publications

In-situ Synthesis of the Anhydrous La(hfac)3 Precursor: A Viable Route to the MOCVD of LaF3

In-situ Synthesis of the Anhydrous La(hfac)3 Precursor: A Viable Route to the MOCVD of LaF3

MOCVD of YF₃ and Y_1–_xEr_xF₃ Thin Films from Precursors Synthesized In Situ

Doping dependence of the chemical potential and surface electronic structure in YBa2Cu3O6+x and La2-xSrxCuO4 using hard x-ray photoemission spectroscopy

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X-ray photoelectron study of Ca, Sr and Ba ion chemical states in high-Tc superconductors

Cited by 20 publications

References 34 publications

In-situ Synthesis of the Anhydrous La(hfac)3 Precursor: A Viable Route to the MOCVD of LaF3

In-situ Synthesis of the Anhydrous La(hfac)3 Precursor: A Viable Route to the MOCVD of LaF3

MOCVD of YF3 and Y1–xErxF3 Thin Films from Precursors Synthesized In Situ

Doping dependence of the chemical potential and surface electronic structure in YBa2Cu3O6+x and La2-xSrxCuO4 using hard x-ray photoemission spectroscopy

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Product

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About

MOCVD of YF₃ and Y_1–_xEr_xF₃ Thin Films from Precursors Synthesized In Situ