Effects of Intermixing in Sb2Te3/Ge1+xTe Multilayers on the Thermoelectric Power Factor

Over the past few decades, telluride-based chalcogenide multilayers, such as PbSeTe/PbTe, Bi2Te3/Sb2Te3, and Bi2Te3/Bi2Se3, were shown to be promising high-performance thermoelectric films. However, the stability of performance in operating environments, in particular, influenced by intermixing of the sublayers, has been studied rarely. In the present work, the nanostructure, thermal stability, and thermoelectric power factor of Sb2Te3/Ge1+xTe multilayers prepared by pulsed laser deposition are investigated by transmission electron microscopy and Seebeck coefficient/electrical conductivity measurements performed during thermal cycling. Highly textured Sb2Te3 films show p-type semiconducting behavior with superior power factor, while Ge1+xTe films exhibit n-type semiconducting behavior. The elemental mappings indicate that the as-deposited multilayers have well-defined layered structures. Upon heating to 210 °C, these layer structures are unstable against intermixing of sublayers; nanostructural changes occur on initial heating, even though the highest temperature is close to the deposition temperature. Furthermore, the diffusion is more extensive at domain boundaries leading to locally inclined structures there. The Sb2Te3 sublayers gradually dissolve into Ge1+xTe. This dissolution depends markedly on the relative Ge1+xTe film thickness. Rather, full dissolution occurs rapidly at 210 °C when the Ge1+xTe sublayer is substantially thicker than that of Sb2Te3, whereas the dissolution is very limited when the Ge1+xTe sublayer is substantially thinner. The resulting variations of the nanostructure influence the Seebeck coefficient and electrical conductivity and thus the power factor in a systematic manner. Our results shed light on a previously unreported correlation of the power factor with the nanostructural evolution of unstable telluride multilayers.

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:15

Enthalten in:

ACS applied materials & interfaces - 15(2023), 18 vom: 10. Mai, Seite 22672-22683

Sprache:

Englisch

Beteiligte Personen:

Zhang, Heng [VerfasserIn]
Ahmadi, Majid [VerfasserIn]
Ginanjar, Wastu Wisesa [VerfasserIn]
Blake, Graeme R [VerfasserIn]
Kooi, Bart J [VerfasserIn]

Links:

Volltext

Themen:

EDX mapping
Intermixing
Journal Article
Pulsed laser deposition
Sb2Te3/Ge1+xTe multilayer
Thermoelectric power factor

Anmerkungen:

Date Completed 10.05.2023

Date Revised 15.05.2023

published: Print-Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.1021/acsami.3c00869

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM356255085