Record High Power Factor and Low Thermal Conductivity in Amorphous/PbTe/Amorphous Multiple Quantum Wells

Abstract

Quantum well (QW) superlattice is one of the proposals to improve the thermoelectric properties and provide a rich platform for the next generation of thermoelectric device. Previous QW have two main challenges that need to be addressed: i) decrease the electron tunneling across the layers in the semiconductor‐based multiple QWs (MQW), and ii) decrease the thermal conductivity in the oxide‐based MQW. Herein, the study demonstrates amorphous based PbTe/amorphous‐STO MQWs with ultrahigh power factor of 40.9 µW cm−1 K−2 and record low thermal conductivity of ≈0.49 W m−1 K−1 at room temperature. The high performance of PbTe/amorphous‐STO MQWs is attributed to strong quantum confine effect and its intrinsic low thermal conductivity of amorphous superlattice structure. The results open up a new avenue toward modulating thermoelectric properties beyond traditional MQWs of thermoelectric materials.

Interfacial Distortion of Sb2Te3–Sb2Se3 Multilayers via Atomic Layer Deposition for Enhanced Thermoelectric Properties

“…Interface scattering arises when carriers traverse between different layers, leading to mobility restrictions and impacting overall mobility . Additionally, potential barriers within the superlattice structure can obstruct the interlayer transport of charge carriers, further reducing mobility . Furthermore, interface effects can induce the formation of interface states, which act as scattering centers for carriers, contributing to additional charge scattering and a subsequent decrease in mobility .…”

“…Our theoretical simulations provided strong confirmation of the results (see Tables S5–S7 in the Supporting Information). Phonons with mid- to long-wavelengths scattering are enhanced at the heterojunction interfaces, which is considerably more efficient than scattering at normal grain boundaries. ,, Consequently, the m* increases and the thermal conductivity decreases simultaneously, leading to a high zT value of 0.38 for the sample Sb 2 Te 3 :Sb 2 Se 3 = 5:5 (nm).…”

“… 25 Additionally, potential barriers within the superlattice structure can obstruct the interlayer transport of charge carriers, further reducing mobility. 26 Furthermore, interface effects can induce the formation of interface states, which act as scattering centers for carriers, contributing to additional charge scattering and a subsequent decrease in mobility. 27 Conversely, an inverse trend is evident in the Seebeck coefficient results.…”