Achieving Out-of-Plane Thermoelectric Figure of Merit ZT = 1.44 in a p-Type Bi₂Te₃/Bi_0.5Sb_1.5Te₃ Superlattice Film with Low Interfacial Resistance

Abstract

Recently, low-dimensional superlattice films have attracted significant attention because of their low dimensionality and anisotropic thermoelectric (TE) properties such as the Seebeck coefficient, electrical conductivity, and thermal conductivity. For these superlattice structures, both electrons and phonons show highly anisotropic behavior and exhibit much stronger interface scattering in the out-of-plane direction of the films compared to the in-plane direction. However, no detailed information is available in the literature for the out-of-plane TE properties of the superlatticebased films. In this report, we present the out-of-plane Seebeck coefficient, thermal conductivity, and electrical properties of p-type Bi 2 Te 3 /Bi 0.5 Sb 1.5 Te 3 (bismuth telluride/bismuth antimony telluride, BT/BST) superlattice films in the temperature range of 77−500 K. Because of the synergistic combination of the energy filtering effect and low interfacial resistance of the superlattice structure, an impressively high ZT of 1.44 was achieved at 400 K for the 200 nm-thick p-type BT/BST superlattice film, corresponding to a 43% ZT enhancement compared to the pristine p-BST films with the same thickness.

Engineering Copper Iodide (CuI) for Multifunctional p‐Type Transparent Semiconductors and Conductors

“…[ 132 , 133 ] The generated power output compared to the well‐known thermoelectric bulk component (Sb 2 Te 3 /Bi 2 Te 3 , ZT value ≈1). [ 134 , 135 ] These studies not only demonstrated the novelty of CuI as a transparent thermoelectric material, but also accelerated the realization of thermoelectric windows, body‐heat‐driven wearable electronics, and on‐chip cooling or power reversion for miniaturized chips. To further enhance the thermoelectric performance of CuI, the film conductivity should be improved.…”

Dimensionality effects in high‐performance thermoelectric materials: Computational and experimental progress in energy harvesting applications

“…137 This approach leads to a great enhancement in ZT of the TE of superlattices. Another work reported that the superlattice structures PbTe/PeSe 0.98 Te 0.02 on the BaF 2 surface shows improved TE performance and corresponding ZT values reached $1.6 at 300 K and $3.5 at 570 K. 16,17,133 Park et al 138 prepared p-type of superlattice structure Bi 2 Te 3 /Bi 0.5 Sb 1.5 Te 3 displayed impressive TE ZT values of 1.44 at 400 K which is 43% higher than the original structure. Priyadarshi et al 139 analyzed various designs of superlattices and concluded that a Gaussian distribution with superlattices thick barrier provides very high ZT values.…”

A Comprehensive Review of Strategies and Approaches for Enhancing the Performance of Thermoelectric Module

“…Harman et al [59,62,66] manufactured a superlattice structure with PbTe/PeSe 0.98 Te 0.02 on top of the BaF 2 substrate, and the structure achieved ZT~1.6 and ZT~3.5 at 300 K and 570 K, respectively. Lee et al [67] presented thermoelectric properties of p-type Bi 2 Te 3 /Bi 0.5 Sb 1.5 Te 3 superlattice films. These achieved an impressively high ZT of 1.44 at 400 K, 43% higher than the original.…”