Temperature-dependent thermal conductivity of MBE-grown epitaxial SrSnO3 films

As an ultrawide bandgap (similar to 4.1 eV) semiconductor, single crystalline SrSnO3 (SSO) has promising electrical properties for applications in power electronics and transparent conductors. The device performance can be limited by heat dissipation issues. However, a systematic study detailing its thermal transport properties remains elusive. This work studies the temperature-dependent thermal properties of a single crystalline SSO thin film prepared with hybrid molecular beam epitaxy. By combining time-domain thermoreflectance and Debye-Callaway modeling, physical insight into thermal transport mechanisms is provided. At room temperature, the 350-nm SSO film has a thermal conductivity of 4.4 W m(-1) K-1, similar to 60% lower than those of other perovskite oxides (SrTiO3, BaSnO3) with the same ABO(3) structural formula. This difference is attributed to the low zone-boundary frequency of SSO, resulting from its distorted orthorhombic structure with tilted octahedra. At high temperatures, the thermal conductivity of SSO decreases with temperature following a similar to T-0.54 dependence, weaker than the typical T-1 trend dominated by the Umklapp scattering. This work not only reveals the fundamental mechanisms of thermal transport in single crystalline SSO but also sheds light on the thermal design and optimization of SSO-based electronic applications.

Automated summary

As an ultrawide bandgap semiconductor, single crystalline SrSnO3 (SSO) shows potential for power electronics and transparent conductor applications, but its device performance can be limited by heat dissipation issues. This study investigates the temperature-dependent thermal properties of a single crystalline SSO thin film and provides physical insights into its thermal transport mechanisms. The results reveal that the thermal conductivity of the SSO film is lower than other perovskite oxides at room temperature, attributed to its unique distorted orthorhombic structure. At high temperatures, the thermal conductivity of SSO decreases with temperature following a weaker dependence than typical trends dominated by Umklapp scattering. This work not only improves our understanding of thermal transport in single crystalline SSO but also has implications for the thermal design and optimization of SSO-based electronic applications.