In this study, the structural and crystallographic properties of Cr₂Se₃ under various conditions, including Cr vacancies, Ti doping, and temperature changes, were investigated. The experimental X-ray diffraction (XRD) results revealed preferential orientation, strain effects, and defect-induced peak shifts, with notable differences between bulk and thin-film samples. The simulated XRD patterns demonstrate that Cr vacancies cause lattice contraction, resulting in right shifts of the peaks, whereas Ti doping induces lattice expansion, observed as left shifts, irrespective of Wyckoff site substitution. Temperature-dependent studies revealed unusual lattice contractions at elevated temperatures, suggesting non-standard thermal behavior. These findings underscore the tunability of Cr₂Se₃ properties through defect engineering, doping, and thermal optimization, providing valuable insights for tailoring material characteristics for advanced applications.

Keywords: Cr₂Se₃, X-ray diffraction, Density functional theory, Wyckoff site substitution, Defect engineering