Precursive stage of crystallization of willemite-type Zn₂GeO₄ from a germanate glass: Inelastic light scattering and TEM studies

Abstract

We performed in-situ observation of inelastic light scattering in a Li₂O-ZnO-GeO₂ system glass, which crystallizes the wide-gap semiconductive willemite-type Zn₂GeO₄ nanocrystal, during heating process in order to examine the precursive stage of crystallization of willemite phase in the glass. The TEM observation was also carried out to check the structural evolution during the precursive stage. It was suggested that the presence of nanometric Zn-enriched region, which is generated by a liquid-liquid phase-separation, in the supercooledliquid state leads to provides the willemite-type Zn₂GeO₄ including an excess of interstitial Zn-defect.