Free-Volume Nanostructurization in Ga-Modified As2Se3 Glass

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Glassy arsenic selenide (As2Se3) exhibits intrinsic nanostructurization and free-volume voids.
• Gallium (Ga) doping is explored to modify the structure and properties of As2Se3.

Purpose of the Study:

• To investigate the stages of nanostructurization in Ga-doped As2Se3 glass.
• To understand the evolution of free-volume voids and phase separation with increasing Ga content.

Main Methods:

• Positron annihilation lifetime spectroscopy (PALS) to probe free-volume voids.
• X-ray powder diffraction (XRD) for crystalline phase identification.
• Scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX) for microstructural and compositional analysis.

Main Results:

• Ga doping modifies the native void structure of As2Se3.
• At low Ga content (<3 at.%), voids associated with As2Se4/2 units dominate.
• Higher Ga content induces crystalline Ga2Se3 precipitation and growth, altering void characteristics.

Conclusions:

• Nanostructurization in Ga-doped As2Se3 involves phase separation, nucleation, and growth.
• The study reveals a transition in void structure and trapping mechanisms with increasing Ga concentration.
• Ga doping significantly influences the free-volume evolution and phase stability of As2Se3 glassy alloys.