The development of thermoelectric devices faces not only the challenge of
optimizing the Seebeck coefficient, the electrical and thermal conductivity of
the active material, but also further bottlenecks when going from the
thermoelectric material to an actual device, e.g., the dopant diffusion at the
hot contact. We show that for large bandgap thermoelectrics another aspect can
dramatically reduce the efficiency of the device: the formation of Schottky
barriers. Understanding the effect, it can then be fixed rather cheaply by a
two-metals contact solution
