High room-temperature figure of merit of thin layers prepared by laser ablation from Bi 2 Te 3 target

The figure of merit ZT is measured by a Harman method on simple devices prepared on single thermoelectric layers of different thicknesses. The thermoelectric layers are prepared at different conditions by laser ablation from Bi 2 Te 3 target. The best measured figure of merit ZT is for our devices ZT = 2.65 . This result is comparable with the results obtained on superlattices. ZT oscillated with the thickness of the layers. On some devices the Seebeck coefficient is measured and using conductivity measurements along the thermoelectric layers the thermal conductivity is estimated from ZT . The low thermal conductivity of samples is explained by the quantum size effect and by existence of few phases of type Bi 2 ( m + n ) Te 3 n in the thermoelectric layers.