Role of Phosphorus in the Crystallization of Bi-modified Chalcogenide Glasses

Chalcogenide glasses possess a variety of unique properties, such as high optical transparency in a wide infrared region of spectrum, large optical nonlinearities, and excellent molding and fiber drawing capabilities, which grant them many useful applications in modern photonics. By modifying Ge-Te-Se glass matrices with other elements such as Bi and P, further interesting properties can be achieved, such as thermoelectric effect, change in the conductivity type, or rapid crystallization at the elevated temperatures or under photoexposure. In this work we report the thermal stability and crystallization kinetics studies for Bi-P-Ga-Ge-Se-Te glasses, with P content up to 10 at.%. Our results show that as the concentration of P increases in the composition, the thermal stability of the glass also increases. Conversely, if Bi concentration increases, thermal stability of the glass decreases and rapid crystallization peaks are observed with differential scanning calorimetry. The latter property can be used for phase-change memory applications.