Korean Journal of Materials Research ISSN:1225-0562(Print) 2287-7258(Online) 한국재료학회지

We develop a purification process of Hg₂Br₂ raw powders using a physical vapor transport(PVT) process, which is essential for the fabrication of a high performance acousto-optic tunable filter(AOTF) module. Specifically, we characterize and compare three Hg₂Br₂ powders: Hg₂Br₂ raw powder, Hg₂Br₂ powder purified under pumping conditions, and Hg₂Br₂ powder purified under vacuum sealing. Before and after purification, we characterize the powder samples through X-ray diffraction and X-ray photoelectron spectroscopy. The corresponding results indicate that physical properties of the Hg₂Br₂ compound are not damaged even after the purification process. The impurities and concentration in the purified Hg₂Br₂ powder are evaluated by inductively coupled plasma-mass spectroscopy. Notably, compared to the sample purified under pumping conditions, the purification process under vacuum sealing results in a higher purity Hg₂Br₂ (99.999 %). In addition, when the second vacuum sealing purification process is performed, the remaining impurities are almost removed, giving rise to Hg₂Br₂ with ultra-high purity. This high purification process might be possible due to independent control of impurities and Hg₂Br₂ materials under the optimized vacuum sealing. Preparation of such a highly purified Hg₂Br₂ materials will pave a promising way toward a high-quality Hg₂Br₂ single crystal and then high performance AOTF modules.