Thermoelectric Properties of Heteroepitaxial PbTe Films On Si

Epitaxial PbTe-films are grown heteroepitaxially on 3 inch Si(111)-wafers, covered with an ultrathin (3 nm) CaF2-layer for compatibility reasons. Previous work has shown the good quality of such films despite the large lattice and thermal mismatch between PbTe and Si. We report on measuremeents of the thermoelectric power of n- and p-type PbTe films obtained for carrier concentrations between 10 17 1/cm³ and 10 18 1/cm³ Determination of the power-factor alfa²alfa as a function of temperature shows a maximum below 300 K for these films. The data are compared with results of T. C. Harman et. al.k [2] on PbTe epitaxial films on BaF2(111)-substrates. The results show that heteroepitaxial films on Si may be intersting for thermelectric applications. As already shown for infrared sensor applications using PbTe films as quantum well detectors, necessary readout electronic could be monolitically integrated on the Si-wafer.