From micro-structured materials to layered compounds: strategies for thermal energy management

This thesis investigates advanced materials and innovative approaches for thermal energy management, with the goal of addressing the global demand for sustainable energy generation and conversion technologies. Through a combination of experimental and computational techniques, including near- and far-field spectroscopy, thermal emission, Seebeck coefficient, and resistivity measurements, this work explores both the mechanisms of heat transfer and energy conversion. High-quality epitaxial samples grown via Molecular Beam Epitaxy and electromagnetic simulations provided the foundation for a detailed analysis of these processes. The research is divided into two main areas. The first focuses on thermal radiation emission from micro-structured materials, such as 3D microporous graphene and silicon carbide (SiC), revealing how artificial patterning can enhance emissivity and modify optical and thermal properties through phonon-polariton excitations. The second area addresses the development and characterization of epitaxial thermoelectric materials, including Bi₂Se₃, Bi₂Te₃, Sb₂Te₃, and (BiₓSb₁₋ₓ)₂Te₃ thin films, assessing their transport and thermoelectric performance. Additionally, the optical properties of (GeTe)ₙ(Sb₂Te₃)ₘ layered alloys are examined, highlighting their potential both as phase-change and thermoelectric materials. Overall, this work contributes to the understanding and optimization of materials capable of efficiently managing thermal energy, paving the way for environmentally friendly solutions in energy harvesting, conversion, and storage.