schinke_2015#
C. Schinke, P. C. Peest, J. Schmidt, R. Brendel, K. Bothe, M. R. Vogt, I. Kröger, S. Winter, A. Schirmacher, S. Lim, H. T. Nguyen and D. MacDonald, “Uncertainty analysis for the coefficient of band-to-band absorption of crystalline silicon”, AIP Adv. 5, 067168 (2015)
Source record · Catalogue · Review register
DOI: 10.1063/1.4923379
Source kind: measurement
Recorded technique: Four methods at ISFH, PTB and ANU, each with a GUM uncertainty analysis (Sections II-III), combined into one data set (Section IV). Spectroscopic ellipsometry (J. A. Woollam M-2000 UI, 60-80 deg, WVASE32; a Si slab under a few nm of SiO2 with Herzinger’s 2008 thermal-oxide constants; Monte-Carlo uncertainty) at 250-930 nm on a front-polished Czochralski p-type wafer, 5 Ohm cm, 1284 um. Above 650 nm the ellipsometric alpha is replaced by a Tauc parametrisation alpha = [beta (hc/lambda - E_G)]^2 fitted at 650-1050 nm to the ellipsometry and the reflectance/transmittance data, its uncertainty interpolated between those of the data at 650 and 930 nm (PDF p. 9). Reflectance and transmittance (RT; a Cary 5000 spectrophotometer with an integrating sphere at ISFH; a Cary 6000i and PTB’s reference reflectometer at PTB) on double-side-polished Czochralski p-type wafers, 4-6 Ohm cm, 653.0 and 1284.0 um thick; the RT alpha is corrected for free-carrier absorption with the parametrisation of Green’s 1995 book (Ref. 56) at 3e15 cm^-3 (below 2 % below 1150 nm). Electroluminescence (EL, 1100-1250 nm, polished lab cells, 711 um, 2.5 Ohm cm) scaled to the RT alpha at 1100-1140 nm (scale uncertainty 2.8 %); photoluminescence (PL, 1200-1450 nm, textured Al2O3-passivated wafers) scaled to the EL alpha at 1200-1250 nm; spectral responsivity (SR) of solar cells at PTB (1100-1320 nm). Overlapping results are combined as weighted means (with hidden correlations for the ISFH RT data). Sample temperature 295 +- 1 K (ellipsometry, RT) and 295 +- 0.5 K (EL, PL, SR); the temperature uncertainty is included through the paper’s c_T (Eq. 22).
Materials in structured entries: Si
Dataset quantities: absorption_coefficient
Contents: 1 dataset; 0 formulas.
Curation notes#
Article 067168 = PDF pages 1-23 (page 1 is the publisher’s cover sheet); Table I (Appendix A) is on PDF pp. 20-21. Identity checked against the first pages. Open access (CC BY 3.0).
WHAT IS TABULATED. Table I (‘Coefficient of band-to-band absorption of crystalline silicon at 295 K and its relative uncertainty as determined in this work’): alpha_bb (cm^-1, four significant figures, each with its own power of ten) and the relative expanded uncertainty U(alpha_bb)/alpha_bb (%), 250-1450 nm at 10 nm steps (121 rows). Caption: ‘The uncertainty is specified for a coverage factor k = 2 and rounded to two significant digits’; the GUM expanded uncertainty with k = 2, ‘approximately 95 %’ (PDF p. 6), recorded as relative_rows with level ‘2 sigma’. alpha_bb is alpha less free-carrier absorption (corrections below 2 % (RT), 4.5 % (EL) and about 6 % (industrial SR cells), each with an uncertainty equal to itself, rectangular). The paper prints only alpha: no n or k. The wavelength medium is not stated; the difference between air and vacuum wavelengths (about 0.3 nm) is far below the 10 nm grid and the uncertainties. The paper says Table I is also provided in digital form as supplementary material (Ref. 58); that file is not in the library, and Table I is complete without it.
UNCERTAINTY (k = 2). 0.18-0.66 % at 250-360 nm, rising through the absorption edge near 370 nm to 13 % at 630-670 nm (the ellipsometry’s signal-to-noise falls as k/n falls), down to 0.98-2 % at 900-1060 nm (RT), then rising to 10-13 % at 1170-1220 nm, 22 % at 1240-1250 nm, 36 % at 1350 nm and 180 % at 1450 nm. The abstract and conclusion quote ‘0.4% at 250 nm’ and ‘12% at 1200 nm’, where Table I prints 0.26 and 11 (12 at 1190 and 1210 nm): the table’s values are recorded; the paper does not explain the difference. From 650 nm into the RT range the values are the Tauc parametrisation’s, a smooth function, not individual measurements.
TEMPERATURE. Table II (Appendix B, PDF pp. 21-22) gives c_T = (1/alpha_bb) d alpha_bb/dT at 295 K (Eq. 22), 250-1450 nm, the mean of the ISFH ellipsometry, the ANU PL and Green (2008)’s coefficients, for use as alpha(T) = alpha(T0) (T/T0)^b, b = c_T T0 (Eqs. 23-24). A normalised coefficient of alpha: no quantity, not extracted.
COMPARISON IN THE PAPER (Fig. 16, PDF p. 19): deviations from the literature ‘of the order of up to 30% relative’; good agreement with Green (2008, green_2008) except beyond 1200 nm, where Green’s alpha had given luminescence spectra at odds with measurement.
REFRACTIVEINDEX.INFO. main/Si/nk/Schinke.yml (data/external/refractiveindex_info) gives n and k at 0.25-1.45 um citing this paper and M. R. Vogt’s PhD thesis (2015); its n is not printed in the paper (it comes from the thesis) and is not used here; see the register entry for the comparison of k.
Recorded bibliographic identity status: VALIDATED. This concerns identification of the source; it does not establish the scientific correctness of its contents.
Datasets#
schinke_2015/alpha_295K#
{
"id": "alpha_295K",
"material": "Si",
"file": "Si/schinke_2015__alpha_295K.csv",
"table": "tbl_80266e561237",
"quantity": "absorption_coefficient",
"unit": "cm-1",
"abscissa_unit": "nm",
"use": "primary",
"parameters": {
"base": "e",
"temperature_k": 295,
"form": "bulk",
"technique": "ellipsometry, reflectance/transmittance, luminescence and spectral responsivity, combined"
},
"uncertainty": {
"level": "2 sigma",
"relative_rows": {
"250": 0.0026,
"260": 0.0028,
"270": 0.0027,
"280": 0.0028,
"290": 0.0018,
"300": 0.0019,
"310": 0.002,
"320": 0.0025,
"330": 0.0032,
"340": 0.003,
"350": 0.0043,
"360": 0.0066,
"370": 0.011,
"380": 0.017,
"390": 0.024,
"400": 0.03,
"410": 0.037,
"420": 0.043,
"430": 0.05,
"440": 0.055,
"450": 0.061,
"460": 0.068,
"470": 0.075,
"480": 0.078,
"490": 0.08,
"500": 0.083,
"510": 0.089,
"520": 0.093,
"530": 0.11,
"540": 0.12,
"550": 0.11,
"560": 0.11,
"570": 0.1,
"580": 0.1,
"590": 0.11,
"600": 0.11,
"610": 0.12,
"620": 0.12,
"630": 0.13,
"640": 0.13,
"650": 0.13,
"660": 0.13,
"670": 0.13,
"680": 0.12,
"690": 0.12,
"700": 0.11,
"710": 0.11,
"720": 0.1,
"730": 0.098,
"740": 0.093,
"750": 0.089,
"760": 0.084,
"770": 0.079,
"780": 0.074,
"790": 0.07,
"800": 0.065,
"810": 0.06,
"820": 0.055,
"830": 0.051,
"840": 0.046,
"850": 0.041,
"860": 0.037,
"870": 0.032,
"880": 0.028,
"890": 0.023,
"900": 0.019,
"910": 0.015,
"920": 0.012,
"930": 0.01,
"940": 0.0098,
"950": 0.01,
"960": 0.011,
"970": 0.012,
"980": 0.013,
"990": 0.014,
"1000": 0.014,
"1010": 0.014,
"1020": 0.015,
"1030": 0.016,
"1040": 0.018,
"1050": 0.019,
"1060": 0.02,
"1070": 0.022,
"1080": 0.022,
"1090": 0.023,
"1100": 0.025,
"1110": 0.028,
"1120": 0.032,
"1130": 0.041,
"1140": 0.058,
"1150": 0.078,
"1160": 0.088,
"1170": 0.1,
"1180": 0.11,
"1190": 0.12,
"1200": 0.11,
"1210": 0.12,
"1220": 0.13,
"1230": 0.17,
"1240": 0.22,
"1250": 0.22,
"1260": 0.2,
"1270": 0.18,
"1280": 0.17,
"1290": 0.18,
"1300": 0.18,
"1310": 0.2,
"1320": 0.24,
"1330": 0.28,
"1340": 0.33,
"1350": 0.36,
"1360": 0.38,
"1370": 0.42,
"1380": 0.5,
"1390": 0.58,
"1400": 0.75,
"1410": 0.88,
"1420": 1.2,
"1430": 1.4,
"1440": 1.7,
"1450": 1.8
}
}
}
Table I, PDF pp. 20-21 (tbl_80266e561237, tbl_8c2f326870f4): alpha_bb of crystalline silicon at 295 K, 250-1450 nm, 121 rows (1.804e6 to 9.447e-9 cm^-1), each cell’s power of ten in e-notation. Relative uncertainty per row from the table (k = 2), checked against the table by the extraction script. Combined from ellipsometry, RT, EL, PL and SR; from 650 nm into the RT range a Tauc parametrisation (source notes).
Formulas#
No formulas are recorded.
Corrections#
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 review register for the checks and decisions.