Constructing of amorphous/PbSe/amorphous multiple quantum wells with record high thermoelectric properties

Quantum well (QW) is one of the proposals to improve the thermoelectric properties. However, previous studies have shown that the large electron and phonon tunneling across the layers in semiconductor-based QWs and oxide-based QWs, respectively, are the two main challenges that need to be addressed. In this work, PbSe/amorphous-SrTiO ₃ ( α-STO) supperlattices with a multiple quantum-well (MQW) structure can overcome both limitations. We demonstrate that the PbSe/ α-STO MQW shows a high power factor of ∼ 24.5 μW cm ⁻¹K ⁻² at room temperature due to the strong quantum confine effect. In addition, the amorphous-SrTiO ₃ layer can engender intrinsically low thermal conductivity (0.27± 0.05 W m ⁻¹ K ⁻¹). The maximum estimated zT value is 2.7 for PbSe/ α-STO MQW at room temperature, which is more than 1800 % higher than that of pure PbSe films ( zT = 0.15).