The low temperature thermoelectric properties of CuxTiSe2−ySy

The low temperature thermoelectric properties of TiSe2, co-doped with Cu and S, are reported. Partial S substitution for Se changes the magnitude of the indirect bandgap, while the Cu-doping independently controls the n-type carrier concentration. The Seebeck coefficients are negative, in the range of −50 to −200 μV K−1, and the resistivities are 0.1–10 mΩ cm. The thermal conductivity for the sample with the largest thermoelectric power factor was found to be relatively low, 3–4 W m−1 K−1, and decreases with decreasing temperature. The thermoelectric efficiencies for the best materials found in this system, typified by Cu0.02TiSe1.7S0.3, were largest at 0.07 at 300 K and decreased to 0.01 at 75 K.