Liquid Surface Tension Measurements by Analysis of Solid-State Curvatures; The Surface Tension of Liquid Germanium

Abstract

A procedure based upon zone-melting techniques has been developed for determining liquid-gas surface tension coefficients for liquids at their melting points by analysis of the surface curvatures of solid specimens. The method can give standard deviations of the mean of the order of ±1 percent. It has been calibrated with lead and cadmium to be valid to within at least ±5—10 percent. The most important factors limiting its range of applicability are crystallographic forces which produce facets on the solid and the difficulty of producing and maintaining a clean liquid-gas surface. The surface tension of liquid germanium at its melting point, 934.5°C, in contact with helium or nitrogen has been found to be 632±5 dyne/cm, in good agreement with a previously reported value.

Theoretical Study of a Thermophysical Property of Molten Semiconductors

“…Also, Rhim and Ishikawa fitted their surface tension data for molten Ge [11] as: γ = 583 − 0.08 (T − T m ) (mJ m −2 ), and for molten Si [10,24] Figures 2 and 3 reveal that there is about 6% and 4% difference beween the calculated and the experimental results for Si and Ge, respectively. This may be attributed to the fact that the surface tension of molten silicon and germanium is difficult to measure accurately, and consequently, the available experimental data for the surface tension of molten silicon [1][2][3][4][5] and molten germanium [5][6][7] is currently widely scattered, not only their absolute values but also their temperature dependence, and agreement between the existing experimental data is quite poor (for Si, γ ranges from 720 to 875 mJ/m 2 , whereas the range is 560-632 mJ/m 2 for Ge). The data reported in the literature suffer from experimental problems and the presence of impurities.…”

“…The surface tension is sensitive to even minute surface contamination. However, it has been measured for molten silicon and germanium at the melting points [1][2][3][4][5][6][7] and at different temperatures [8][9][10][11][12]. The surface tension of high-temperature melts is the most needed and the most poorly established property.…”

Emission of charged particles from laser-induced germanium ecton, vacuum spark, and vacuum arc

“…It can be assumed that the transition in emission behavior strongly depends on how the liquid surface can be destroyed by electrostatic forces, expressed as Ucrit/dc-g ≈ (2γ/(εorc)) 1/2 , where γ is the coefficient of surface tension [33]. After vacuum breakdown, i.e., when dc-g can be replaced by rc, the corresponding transition potential becomes Ucrit ≈ (2γrc/(εo)) 1/2 ; for instance, Ucrit = 1164 V for γ = 0.6 N/m and rc = 10 µm for germanium [34]. Thus, evaporation from a "hot" crater becomes less destructive and more localized inside the crater, see Finally, the anodic charge (Q) for Rc values above the measured self-sustaining resistance of 10 Ω are adequately approximated by the relation Q ~ ln(Rc), i.e., Q ~ ln(Ic) is independent from the gate capacitance.…”