Crystallization behaviours of In2.67S4 nanophase in chalcohalide glasses

Abstract

The GeS₂–In₂S₃–CsI chalcohalide glass ceramics with In_2.67S₄ nanocrystallites embedded in the glassy matrix are prepared by melt–quenching and subsequent heating, and the thermal crystallization behaviour of the In_2.67S₄ nanophase is systematically investigated. Evidently, the In_2.67S₄ crystallization is dependent on the In₂S₃/CsI component ratio in the precursor glass: it proceeds when In₂S₃/CsI > 1, and is prohibited when In₂S₃/CsI < 1. In₂S₃/CsI = 1 seems to be the critical point, and the situation is uncertain for the critical samples. Based on Raman spectra analyses, it is concluded that both the [S₃In–InS₃] ethane-like and the [InS₄] tetrahedral units in the precursor glass play key roles in forming the In_2.67S₄ nanocrystals. The present study may provide a guide for the crystallization control of other chalcohalide glasses.