In-Plane Thermal Conductivity Measurements of a Single-Crystalline Thin-Film by the 3ω Method

Wei-Han Tsai^1,2*, Ying-Hsiang Lou², Cheng-Lung Chen², Yang-Yuan Chen²

¹Department of Physics, National Taiwan University, Taipei, Taiwan
²Institute of Physics, Academia Sinica, Taipei, Taiwan

* Presenter:Wei-Han Tsai, email:ham0444@gmail.com

Bi_0.5Sb_1.5Te₃ is a widely known room-temperature thermoelectric material and has been extensively studied the thermal conductivity properties along the specified orientation plane. Especially, the previous research presented the prominent thermal conductivity along with the out of plane direction. Herein, we report the result of the in-plane thermal conductivity of Bi_0.5Sb_1.5Te₃ thin films via the 3ω method. Furthermore, a piece of a specimen is obtained from the artificial scratched thin film that further processed as a wire sample by following the focused ion beam (FIB) treatment. The wire is suspended above a hole on our measurement chip and heated by itself when a current through. Then, we use the lock-in amplifier to gain the 3ω signal and estimate the thermal conductivity along the in-plane direction of our sample. Lastly, an optimal thermal conductivity is around 0.28 ±0.02 W/m-K in 1um thin film with a unique preparation procedure.

Keywords: Thin film, 3ω method, Thermoelectric