Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 37: Thermal Properties

HL 37.2: Vortrag

Donnerstag, 8. September 2022, 16:45–17:00, H34

Can group IV alloys compete in thermoelectrics? — •Oliver Krause¹, Ada Chimenti², Omar Concepción¹, Thorsten Brazda¹, Stefano Roddaro², Detlev Grützmacher¹, and Dan Buca¹ — ¹Peter-Grünberg-Institute 9 (PGI-9), Forschungszentrum Jülich, 52428 Jülich, Germany — ²Dipartimento di Fisica "E. Fermi", Università di Pisa, Largo Bruno Pontecorvo 3, 56127 Pisa, Italy

The thermoelectric effect allows the conversion of heat into electricity. A material suited for efficient thermoelectric power generation using small temperature differences with a base at room temperature is of outmost interest. The figure of merit in thermoelectrics is ZT, indicating how suited a material is for thermoelectric applications. It can be optimized by reducing the thermal conductivity k and increasing the electrical conductivity σ of a material with a large Seebeck coefficient α. Here, we investigate the potential of group-IV alloys GeSn and SiGeSn, a material system compatible to standard Si technology.

We present a study of k of crystalline GeSn alloys deposited by chemical vapor deposition. The differential 3ω technique was used to determine k electrically. Our preliminary data shows that k strongly decreases with increasing the Sn content, reaching values as low as 5 W/m· K at room temperature. The data are compared with previous reports of the same material using Raman thermometry. Using data of the electrical conductivity and modelling of Seeback coefficient, ZT values for both p and n type GeSn layers are calculated.