Thermophysical property measurements on molten semiconductors using 10-s microgravity in a drop shaft

Abstract

The effectiveness of 10-s microgravity on thermophysical property measurements on molten materials, such as molten semiconductors, is discussed. The thermal conductivity of molten InSb was successfully measured under microgravity conditions on board the German sounding rocket TEXUS and in a drop shaft in Hokkaido, Japan. Surface tension measurements using an oscillating drop method was attempted in low gravity using a parabolic flight of the NASA KC-135 aircraft. Combined levitation and microgravity, which can provide a contamination-free and undercooled condition, is recommended as a novel approach to obtain missing thermophysical property data on undercooled melts of semiconductors.

Theoretical Study of a Thermophysical Property of Molten Semiconductors

“…is close to the reported experimental values (for Si; 0.22 [10], 0.28 [25], 0.308 [26] and 0.65 [27], and 0.08 mJ m −2 K −1 for Ge [11]). However, our results may be strictly compared with experimental surface tension data, as a function of temperature for molten Si and Ge, reported by others [22,[28][29][30][31][32]. Therefore, the model looks acceptable and predicts the same order of magnitude values for the temperature dependence of the surface tension of metals (Ga), metalloids (Ge), and nonmetals (Si).…”

Thermal Conductivity Measurements of Liquid Mercury and Gallium by a Transient Hot-Wire Method in a Static Magnetic Field

“…A microgravity condition is an ideal field to suppress the convection caused by a buoyancy force. From this point of view, Hibiya et al measured the thermal conductivity of molten InSb under microgravity using the TEXUS-24 rocket [2] and the drop shaft facility (microgravity of 10 −5 g for 10 s), Japan Microgravity Centre (JAMIC) [3,4]. Nagai et al [5,6] measured the thermal conductivity of molten mercury and silicon under microgravity of 10 −3 g for 1.2 s using the short-duration drop tower facility of the Hokkaido National Industrial Research Institute (HNIRI), Japan.…”

Structure and Properties of Molten Metals

“…The first measurements of the thermal conductivity under microgravity conditions of molten salts and molten semiconductors have been made by Hibiya et al for InSb [99,111], applying the THW technique. More recently, THW was applied to molten Al, Si, and Ni by Fukuyama and coworkers [112].…”