philipp_1971
============

H\. R\. Philipp, "Optical properties of non\-crystalline Si, SiO, SiOx and SiO2", J\. Phys\. Chem\. Solids 32, 1935 \(1971\)

`Source record <https://github.com/LupoLab/optmat/blob/main/src/optmat/data/sources/philipp_1971.toml>`__ · :doc:`Catalogue </the-data/sources>` · :doc:`Review register </register>`

DOI: `10\.1016/s0022\-3697\(71\)80159\-2 <https://doi.org/10.1016/s0022-3697%2871%2980159-2>`__

**Source kind:** measurement

**Recorded technique:** Normal\-incidence reflectance, 1\-26 eV, of fused and crystalline quartz \(Fig\. 1; from the author's earlier note, ref\. 10, Solid State Commun\. 4, 73 \(1966\), philipp\_1966, whose Fig\. 1 has the same caption and 5 per cent offset\), of evaporated SiO and SiO\_x \(x ~ 1\.5\) films and of electron\-beam\-evaporated amorphous Si films; Kramers\-Kronig analysis \(ref\. 19\) with the reflectance extrapolated above 26 eV, constrained by the transmission\-derived absorption coefficients of Fig\. 3 in the transparent regions \(p\. 1939\)\. Films\: SiO by rapid evaporation of silicon monoxide \(30\-80 A/s, p \< 1e\-5 Torr\); SiO\_x by slow evaporation \(2\-5 A/s\) in oxygen near 1e\-4 Torr; O to Si ratios not determined \(p\. 1937\)\.

**Materials in structured entries:** None recorded.

**Dataset quantities:** None recorded.

**Contents:** 0 datasets; 0 formulas.

Curation notes
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Journal pages 1935\-1945 = pdf pages 1\-11\. Identity checked against the first page\. NOTHING IS TRANSCRIBED\: the SiO2 data are in figures only, and the paper's only table is out of scope\.

WHAT THE PAPER HOLDS FOR SiO2 \(figures, not digitised\)\: \- Fig\. 1 \(p\. 1936\)\: reflectance of crystalline and fused quartz against photon energy, 'For clarity, the values for fused quartz have been lowered by 5 per cent' \(caption\)\. \- Fig\. 3 \(p\. 1938\)\: absorption coefficient against energy of amorphous Si, SiO, SiO\_1\.5 and SiO2 films, and \(far right\) crystalline SiO2\. \- Fig\. 4 \(p\. 1939\)\: reflectance of Si, SiO, SiO\_1\.5 and SiO2, 'For clarity the ordinates have been displaced \(see arrows\)' \(caption\)\. \- Fig\. 5 \(p\. 1939\)\: epsilon\_1 and epsilon\_2 of the four materials from the Kramers\-Kronig analysis\. \- Fig\. 7 \(p\. 1941\)\: epsilon\_0,eff \(Eq\. \(1\), the sum rule on epsilon\_2/E\) as a percentage of its value integrated to 26 eV; 'for each of these materials the value of epsilon\_0,eff obtained by integration to 26 eV is close to the optical value epsilon\_0' \(p\. 1940\); SiO2 'is essentially transparent' below 9 eV\. \- Fig\. 8 \(p\. 1942\)\: n\_eff \(Eq\. \(2\)\), the effective number of electrons per SiO2 molecule\: 'For SiO2, the curve for n\_eff is approaching 8 electrons per SiO2 molecule near 26 eV\. There is no direct evidence that this plot will saturate near this value' \(p\. 1941\); the oxides' reflectance falls 'fairly fast' above about 23 eV \(p\. 1942\)\. For Si, n\_eff approaches 4 electrons per atom; for SiO, about 6 per molecule\. \- Text \(p\. 1936\)\: the density ratio of crystalline to fused quartz, 2\.65/2\.20 = 1\.2, while 'the polarizability per unit density for each form is nearly the same'\.

RELATION TO philipp\_1985\. Palik's handbook chapter \(philipp\_1985, Table X\) is the first tabulation of these Kramers\-Kronig results\: its 11\.2\-6\.0 eV n \(tag \[9\]\) cites this paper and Solid State Commun\. 4, 73 \(1966\) \(philipp\_1966\), 'with a slight modification of Philipp's results as described in Weinberg et al\.' \(weinberg\_1979 shifts Philipp's data by \+0\.075 eV to align the first peak\), and its 25\-11\.4 eV n and k are a smooth curve through Philipp's and Lamy's results\. Those tables are curated there; nothing here would add to them without digitising\.

OUT OF SCOPE\. The unlabelled table on p\. 1943 \(tbl\_eaef168b55cf\)\: the statistical distribution of the five Si\-centred tetrahedra, Si\-\(Si\_y O\_\(4\-y\)\), for SiO2, SiO\_1\.5, SiO, SiO\_0\.5 and Si \(a structural model, not an optical quantity\)\. The data for amorphous Si, SiO and SiO\_x films \(Figs\. 2\-6, 8\) are figures only; no material is registered for them \(none is needed\)\.

**Recorded bibliographic identity status:** VALIDATED\_WITH\_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.

Datasets
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No datasets are recorded.

Formulas
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No formulas are recorded.

Corrections
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No dataset errata are recorded in this source record.

Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the :doc:`review register </register>` for the checks and decisions.