1 results about "Phase purity" patented technology

This invention discloses a method for controlling the phases of a Bi-Te-O ternary system, belonging to the field of two-dimensional semiconductor material preparation technology. Using Bi₂Te₃ and Bi₂O₃ powders as reaction sources, controllable growth is achieved on a mica substrate using CVD. By adjusting the growth temperature and system pressure to construct a pressure-temperature synergistic phase diagram, the growth windows for four different phases—elemental Te, Bi₂Te₃, Bi₂TeO₅, and Bi₂O₂Te—were determined and controlled. By utilizing the modulation of the vapor pressure and chemical potential of the precursors by temperature and pressure, the problem of low phase purity caused by differences in precursor reaction concentration and activity in the ternary system is solved, successfully preparing ultrathin two-dimensional Bi₂TeO₅ crystals with a thickness of 3.0–5.7 nm. The preparation method provided by this invention is simple and highly controllable, offering a new technological paradigm for the large-scale and precise preparation of complex ternary two-dimensional systems.