Thermal transport and thermoelectric effects at solid-melt interfaces in semiconductors: Underlying physical phenomena that give rise to Thomson heat in semiconductors*

Partial melting in self-heated nanocrystalline silicon microwires via fast pulses show a drastic asymmetry in melting profiles, where half of a wire may be melted and recrystallized while the other half remain in solid state. This asymmetry, in the direction of the electrical current, point to the significance of Thomson heat close to the solid-melt interfaces in semiconductors. The diffusion of the electron-hole pairs away from the melted regions increase thermal transport via (i) increased electronic convective heat flow and (ii) recombination of the excess carriers away from the melted region. In presence of an electric field a non-equilibrium non-isothermal condition is achieved. Generation (G) of electrons and holes, transport (T), and recombination (R) of the minority carriers downstream, GTR¹, lead to a strong asymmetry in thermal profiles at melt-solid interfaces in semiconductors.

¹G. Bakan, N. Khan, H. Silva, A. Gokirmak, “High-temperature thermoelectric transport at small scales: generation, transport and recombination of minority carriers,” Nature Publications, Scientific Reports 3, 2724, doi:10.1038/srep02724 (2013).