Effects of contact resistance and dopant concentration in metal—Semiconductor thermoelectric coolers

The maximum heat that can be pumped by a metal-semiconductor thermoelectric cooling stage depends strongly on the dopant concentration in the semiconductor and on contact resistance at the metal-semiconductor interface which is cooled. A comparison is made between theoretical models describing these effects and experimental data for GaAs, both taken from original measurements and compiled from the literature. A convenient, new technique for determining the Peltier coefficient and the contact resistance of a metal-semiconductor contact is described. The results indicate that, in the case of GaAs, Au:Ge:Ni alloy contacts are effective in minimizing the contact resistance.