Thermal diffusivities and conductivities of molten germanium and silicon

Thermal diffusivity values of molten germanium and silicon were measured by a laser flash method. Simple but useful sample cell systems were developed to keep the molten germanium and silicon shape uniform for a given thickness. In the present experimental condition, it is necessary to consider the effect of not only the radiative heat loss but also the conductive heat loss at the interface between the molten sample and the cell material under the present experimental conditions. However, the computer simulation results suggest that the conductive heat loss is found to be negligibly small. The thermal diffusivity values of molten germanium and silicon are given in the following equations (unit: m²/s). α_Ge = 1.40 × 10^-8 (T - 1218) + 2.29 × 10^-5 1218 ≤ T ≤ 1398 (unit: K) α_Si = 4.48 × 10^-9 (T - 1685) + 2.23 × 10^-5 1685 ≤ T ≤ 1705 (unit: K).