Fabrication, characterization and numerical modeling of Sb ₂ Se ₃ nano-patterned structures

There has been a renewed and strong interest in phase change materials (PCMs) in many fields beyond traditional memories, due to their optical and electrical tunability aspect. Given their unique characteristic of changing phase and refractive index on-demand from amorphous to crystalline and vice versa via optical or electrical switching, they can be employed in many applications ranging from optical filters to rewritable metasurfaces. Patterning PCMs into self-assembled nanorod structures much smaller than the wavelength in diameter could potentially lead to interesting applications such as controlled chirality, birefringence and anisotropy. Additionally, such nanorod geometries may potentially lead to robust switching over multiple cycles for films of thicknesses well beyond those that are switchable in bulk thin film geometries. In this work, we grow and characterize self-assembled nanorods of antimony selenide PCM, and we characterize the nanostrucutres using ellipsometry and X-ray diffraction. We additionally provide an effective medium approximation (EMA) fit that greatly simplifies future macroscopic devices based on the underlying PCM nanorod geometry.