Domain size effects on thermoelectric properties of p-type Ge0.95Sn0.05 layers grown on GaAs and Si substrates

Thermoelectric properties of Ge 0.95 Sn 0.05 layers with various Ga concentrations (1018–1020 cm−3) grown on GaAs and Si by LTMBE have been investigated. Even for single-crystalline layers, the thermal conductivity has been reduced down to 2.5 Wm−1K−1 by introducing the stacking faults due to microscopic tilt in crystals, which value is 4% of bulk-Ge. The layer possessed a good electrical conductivity and Seebeck coefficient (73% and 79% of bulk-Ge, respectively); hence, a relatively good figure-of-merit (ZT=0.13 at 300 K) was obtained.