Thermoelectric characteristics of n-type polycrystalline silicon carbide and comparison with conventional thermopiles

The characteristics of a thermopile made of n-poly-SiC/p-poly-Si junctions are investigated and compared with conventional n/p-poly-Si and Al/p-poly-Si thermopiles. The n-poly-SiC/p-poly-Si thermopile has the highest output voltage (~8 mV with 360 mW heater power) and exhibits a lower contact resistance than an identical thermopile fabricated from n/p-poly-Si. Also significant is that the n-poly-SiC/p-poly-Si junction displays Ohmic behavior, eliminating the need for metallization at the junction to create the necessary contact. As compared to the other two thermopiles, the n-poly-SiC/p-poly-Si thermopile has a superior Seebeck coefficient (S = 2 mV/K) and thermoelectric figure of merit Z of 9.5 times 10^-4 T^-1 at 250 mW heater power, which is over 20times higher than the others.