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Absolute Measurement of Lattice Spacing d(220) in Floating Zone Silicon Crystal

1995; Institute of Physics; Volume: 34; Issue: 9R Linguagem: Inglês

10.1143/jjap.34.5065

1347-4065

Hiroyuki Fujimoto, Kan Nakayama, Mitsuru Tanaka, Guento Misawa,

Surface Roughness and Optical Measurements

The lattice spacing d 220 of a silicon crystal of National Research Laboratory of Metrology has been measured with a new combined X-ray and optical interferometer, with relative uncertainty of 0.16 ppm. This value is in good agreement with other reported values, whereas the ratio of molar mass M to density ρ measured for this crystal shows discrepancy of around 3 ppm from previously reported ratios. It seems that the conventional route to determining the Avogadro constant from M , ρ and d 220 will require a new characterization technique to estimate the number of silicon atoms in a unit cell volume.