New Chalcogenide Glass-Ceramics Based on Ge-Zn-Se for IR Applications

The consumer market requests infrared (IR) optical components, made of relatively abundant and environmentally friendly materials, to be integrated or attached to smartphones. For this purpose, three new chalcogenides samples, namely Ge_23.3Zn_30.0Se_46.7 (d_GZSe-1), Ge_26.7Zn_20.0Se_53.3 (d_GZSe-2) and Ba_4.0Ge_12.0Zn_17.0Se_59.0I_8.0 (d_GZSe-3) were obtained by mechanical alloying and processed by spark plasma sintering into dense bulk disks. Obtaining a completely amorphous and homogeneous material proved to be difficult. d_GZSe-2 and d_GZSe-3 are glass-ceramics with the amount of the amorphous phase being 19.7 and 51.4 wt. %, while d_GZSe-1 is fully polycrystalline. Doping with barium and iodine preserves the amorphous phase formed by milling and lowers the sintering temperature from 350 °C to 200 °C. The main crystalline phase in all of the prepared samples is cubic ZnSe or cubic Zn_0.5Ge_0.25Se, while in d_GZSe-3 the amorphous phase contains GeSe4 clusters. The color of the first two sintered samples is black (the band gap values are 0.42 and 0.79 eV), while d_GZSe-3 is red (E_g is 1.37 eV) and is transparent in IR domain. These results are promising for future research in IR materials and thin films.