SnSe2 thermal conductivity from optothermal Raman and Stokes/anti-Stokes thermometry

• Published in: Nanotechnology 2024-12, Vol.36 (9)
• Main Authors: Vallin, Micah P, Karkee, Rijan, Kucinski, Theresa M, Zhao, Huan, Htoon, Han, Lee, Chanho, Martinez, Ramon M, Fensin, Saryu J, Zhang, Richard Z, Pettes, Michael T
• Format: Article
• Language: English
• Subjects: 2D materials; anti-Stokes scattering; MATERIALS SCIENCE; Raman thermometry; thermal conductivity; thermoelectrics; tin diselenide
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/1361-6528/ad99df

The optothermal Raman method is useful in determining the in-plane thermal conductivity of two-dimensional (2D) materials that are either suspended or supported on a substrate. We compare this method with the Stokes/anti-Stokes scattering thermometry method, which can play a role in both calibration of Raman peak positions as well as extraction of the local phonon temperature. This work demonstrates that the Stokes/anti-Stokes intensity ratio plays an important role in determining the in-plane thermal conductivity of 2D tin diselenide (SnSe2) dry-transferred onto a polished copper (Cu) substrate. The statistically-averaged thermal conductivity of the 108 ± 24 nm-thick SnSe2 yielded 5.4 ± 3.5 Wm-1 K-1 for the optothermal Raman method, and 2.40 ± 0.81 Wm-1 K-1 for the Stokes/anti-Stokes thermometry method, indicating that the Stokes/anti-Stokes thermometry method to calculate the thermal conductivity of a material can simultaneously increase both precision and accuracy. The uncertainty value was also lowered by a factor of 1.9 from the traditional optothermal Raman method to the Stokes/anti-Stokes thermometry method. The low in-plane thermal conductivity of 2D SnSe2, 1.3–2.9 times lower than bulk, is useful for applications in thermal and electrical energy conversion and thermoelectric devices.