Structure and properties of amorphous silicon-metal alloys: II. The Si1-xTixsystem

Gurman, S. J.; Williams, B.T.; Amiss, J. C.

doi:10.1088/0953-8984/12/27/316

Cited by 8 publications

(5 citation statements)

References 19 publications

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“…Amorphous transition-metal-metalloid alloys are, for large ranges of concentration, composed of different amorphous phases [12][13][14][15][16][17][18][19][20][21][22][23][24], each with its own short-range order, a phenomenon called amorphous phase separation. Based on the two-phase model [8] with the two phases a-Cr 1−x A Si x A (≡phaseA) and a-Cr 1−x B Si x B (≡phaseB), in [1] the Seebeck coefficient of a-Cr 1−x Si x has been calculated with the approximation formula of [1] (equation (32) therein).…”

Section: Calculation Of the Seebeck Coefficient Of A-cr 1−x Si X Alloysmentioning

confidence: 99%

“…For small x there is an excellent agreement between the experimental data and the calculated ones; the calculated height of the step (discontinuity) at υ B = 1/3 agrees with the experimental data. On the other side, the step 2, where, however, for x < 0.43 (corresponding to υ B < 1/3) and x > 0.67 (corresponding to υ A < 1/3), S 0 i = 0 and κ e,i = 0 is set or S 0 i and κ e,i are replaced by 0.03 × S 0 i and 0.03 × κ e,i calculated by equation ( 20) and equation (21), respectively. The latter one is indicated by 3% at the S(−) curve and the former by 0%.…”

Section: The Transport Coefficients Of the Phasesmentioning

confidence: 99%

“…Figure3. The same as figure2, where, however, for x < 0.43 (corresponding to υ B < 1/3) and x > 0.67 (corresponding to υ A < 1/3), S 0 i = 0 and κ e,i = 0 is set or S 0 i and κ e,i are replaced by 0.03 × S 0 i and 0.03 × κ e,i calculated by equation (20) and equation(21), respectively. The latter one is indicated by 3% at the S(−) curve and the former by 0%.…”

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confidence: 99%

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Thermoelectric power in alloys with phase separation (composites)

Sonntag¹

2009

J. Phys.: Condens. Matter

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A thermopower formula is derived for composites: [Formula: see text] (κ(i) and κ are the specific thermal conductivities, S(i) and S are the Seebeck coefficients of the phase i and the composite, respectively, and υ(i) is the volume fraction of the phase i). This formula can be applied for calculating the Seebeck coefficient (thermoelectric power) of amorphous transition-metal-metalloid alloys, for which amorphous phase separation occurs for large ranges of concentration. There are two contributions to S(i), a scattering term and a contribution due to electron transfer between the phases maintaining a common electrochemical potential μ. The theory predicts discontinuities in the concentration dependence of the Seebeck coefficient of metallic composites. It is argued that in amorphous composites these discontinuities occur very precisely at υ(i) = 1/3. This phenomenon can be used to characterize the crystallization kinetics of amorphous alloys. The theory is applied to a- Cr(1-x)Si(x) alloys for calculation of S versus x. Both the calculated S(x) dependence and the discontinuities agree very well with the experimental data, as long as x<0.67; the deviations at x>0.67 are interpreted to be caused by the p-d bonds at the phase boundaries.

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Section: Calculation Of the Seebeck Coefficient Of A-cr 1−x Si X Alloysmentioning

confidence: 99%

Section: The Transport Coefficients Of the Phasesmentioning

confidence: 99%

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confidence: 99%

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Thermoelectric power in alloys with phase separation (composites)

Sonntag¹

2009

J. Phys.: Condens. Matter

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“…The various nano-structural units were identified by proper computer modeling combined with microscopic images [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

GISAXS and GIWAXS analysis of amorphous–nanocrystalline silicon thin films

Juraić¹,

Gracin²,

Šantić³

et al. 2010

Nuclear Instruments and Methods in Physics Research Section B:

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Amorphous-nanocrystalline silicon thin films were deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) on glass substrate with various silicon nanocrystal size distributions and volume fractions. The samples were examined by Grazing Incidence Small Angle X-ray Scattering (GISAXS) and Grazing Incidence Wide Angle X-ray Scattering (GIWAXS) at the Austrian SAXS beamline (Synchrotron Elettra, Trieste) using an X-ray beam energy of 8 keV. The grazing incidence angle varied from the critical angle to 0.2 deg. above the critical angle. This allowed the examination of the samples at different depths, and the distinction of the surface scattering contribution from the particles scattering in the bulk. The sizes of the "particles" obtained from the horizontal and vertical sections of 2D GISAXS patterns were between 2 and 6 nanometers. Since GISAXS is sensitive to electron density differences (contrast) between the scattering bodies and the surrounding matrix, it is not evident whether the particles are nanocrystals or just voids embedded in amorphous matrix. However, the size of the crystals calculated from the line-shape analysis of peaks in GIWAXS spectra and the crystal size distribution obtained from High-Resolution Transmission Electron Microscopy (HRTEM) images agree well with the size of "particles" estimated from GISAXS, strongly indicating that the observed particles are silicon nanocrystals. E-MRSJune 08

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“…In the case of thin film silicon, SAXS has been successfully applied to confirm the crucial role of nano-structure in light-induced degradation, in diffusion of hydrogen, in phase segregation, etc. (Prado et al, 1997;Williamson, 1995;Shinar et al, 1999;Mahan et al, 2001;Gurman et al, 2000). However, since grazing-incidence small-angle X-ray scattering (GISAXS) detects only the presence of objects which have an electron density that differs from the average electron density of the material ('particles'), for a complete analysis this technique has to be combined with other methods.…”

Section: Introductionmentioning

confidence: 99%

Study of amorphous nanocrystalline thin silicon films by grazing-incidence small-angle X-ray scattering

et al. 2007

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Thin Si films, with thicknesses between 100 and 400 nm, were deposited by radio frequency plasma enhanced chemical vapour deposition in silane gas (SiH 4 ) highly diluted by hydrogen. The growing conditions were varied to obtain different degrees of crystal fractions and a variety in individual crystal sizes. The crystalline to amorphous volume fraction, as estimated by Raman spectroscopy, varied from 5 to 45% while the individual crystal sizes varied from 2 to 8 nm. The average density of the samples was estimated by using near infrared spectroscopy and the effective medium approximation. All samples were porous and contained void volume fraction between 15 and 25%. Grazing-incidence small-angle X-ray scattering has been performed at the ELETTRA synchrotron radiation source (Trieste, Italy). The scattering patterns of all examined samples indicate the presence of 'particles' in the 'bulk' of the thin films with gyration radii in the range of 2 to 5 nm. The higher values were found for the samples with a higher crystalline fraction. The size and the size distribution of 'particles' depend upon the deposition conditions. The samples which had been deposited with a higher discharge power and a lower silane fraction had larger particles and the roughness of their surface was higher.

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Structure and properties of amorphous silicon-metal alloys: II. The Si_1-xTi_xsystem

Abstract: Structural and optical measurements have been made on a series of amorphous thin films of Si1-xTix with 0 Show more

Cited by 8 publications

References 19 publications

Thermoelectric power in alloys with phase separation (composites)

Thermoelectric power in alloys with phase separation (composites)

GISAXS and GIWAXS analysis of amorphous–nanocrystalline silicon thin films

Study of amorphous nanocrystalline thin silicon films by grazing-incidence small-angle X-ray scattering

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