Diffusion processes at GeTe/SnTe/Fe contacts

Interdiffusion across the GeTe/SnTe interface was studied in the temperature range 670–870 K. The diffusion coefficient for the SnTe + 10 wt % Ge solid solution was determined as a function of temperature, and the thickness of the SnTe interlayer between GeTe and Fe in cascade thermopiles was optimized for hot-junction temperatures Thot ≤870 K. An equation is derived which relates the strength loss in the GeTe/SnTe contact to Thot and the service life of the thermopile. It is shown that diffusion across the interface between dissimilar materials results in strength loss proportional to the logarithm of the diffusion-zone thickness