Structural Influence on Transport Properties in Epitaxial Copper Selenide Thin Films

Understanding how structural variations impact transport behavior is crucial for designing materials with tailored electronic properties. We investigated the transport properties of epitaxially grown copper selenide thin films via molecular beam epitaxy (MBE) on Al₂O₃ (001) substrates, with precise control over growth conditions to produce either cubic or rhombohedral phases. The films were characterized using Reflection High Energy Electron Diffraction (RHEED), X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), and Energy Dispersive Spectroscopy (EDS). Transport measurements revealed a low-temperature phase transition in the cubic phase, which we suggest may be linked to a charge density wave (CDW). However, no such transition was observed in the rhombohedral phase, potentially due to differences in the band structures between the two phases. This study highlights the role of structure in determining phase transitions and transport properties in copper selenide.