CRYSTALLIZATION OF GALLIUM LANTHANUM SULFIDE GLASSES

The crystallization of gallium lanthanum sulfide (GLS) glasses of comp osition (100 - x)Ga2S3. xLa(2)S(3) (mol%) has been analyzed using X-ra y diffraction, and optical and transmission electron microscopy. The m ajor crystalline phase, X, was found to be different from the La3.33Ga 6S14 phase reported previously in similar compositions. X was the prim ary phase present and was observed in all samples, forming on quenchin g as well as on subsequent heat treatment. The phase occurred as spher ulites composed of lamellae, approximately 1 mu m wide and all of the same orientation. A small quantity of crystals of Ga2S3 (20 nm) were o bserved to grow discontinuously between the lamellae. Electron diffrac tion and energy dispersive X-ray analysis suggested that phase X was m onoclinic and had approximately a 2:1 Ga2S3:La2S3 ratio.