DIFFRACTOMETRIC STUDY OF STRUCTURAL PHASE TRANSFORMATIONS IN Cu2−xS AND Cu2−xFe0.05S CRYSTALS

In the article, the diffractogram analysis of phase structural transformations at various temperatures in non-stoichiometric Cu1.75S and Cu1.70Fe0.05S, Cu1.80S and Cu1.75Fe0.05S crystals is carried out. The phase composition of each crystal at the room temperature is determined, and all structural transformations occurring in the crystals depending on the temperature are recorded. X-ray diffractometric studies on Cu2−xFe0.05S monocrystals shown that with increasing temperature, the (FCC)2 (FCC- face-centered cubic) phase gradually merges with the (FCC)1 phase, associated with the yurlite phase, and the phase associated with anilite. Thus, the rombic (anilite) and monoclinic (yurlite) phases combine into a single (FCC)1. Structural transformations and phase changes in the studied crystals affect electrical conductivity and carrier mobility, making these materials suitable for semiconductors, solar panels, and other electronic devices. At the same time, changes in the crystal structure can influence optical properties, such as light absorption and reflection, which makes them attractive for optoelectronic devices and sensors. The ability of the material to undergo transformations at high temperatures while maintaining structural integrity makes it useful for thermoelectric applications and as components in high-temperature devices.