The optical spectra characterization of Cr²⁺:ZnSe polycrystalline synthesized by direct reaction of Zn–Cr alloy and element Se

Cr²⁺:ZnSe materials have attracted much attention as candidates for mid-infrared laser source either in the form of polycrystalline powders, or bulk ceramics, single crystals and nano-materials. In this work, a novel method for synthesizing Cr²⁺:ZnSe polycrystalline by direct reaction of Zn–Cr alloy and element Se (DRAE) was proposed. The zinc alloy containing 0.1 at% Cr was prepared by dissolving Cr in zinc liquid in a closed quartz ampoule. X-ray diffraction (XRD) results showed that the synthesized Cr²⁺:ZnSe polycrystalline was with a Zinc-blend structure. X-ray photoelectron spectroscopy (XPS) spectra showed that there was no un-reacted element of Zn, or Se. Cr²⁺ ions successfully and uniformly doped into ZnSe crystal lattice, which is confirmed by the diffuse reflectance spectrum, Raman spectrum and mid-infrared photoluminescence spectra. Furthermore, the sample showed excellent mid-infrared properties without luminescence quenching in the region 1800–3000 nm, and the decay-time was about 5 μs. The as-synthesized Cr²⁺:ZnSe polycrystalline meets the requirement for the preparation of mid-infrared ceramic or single crystals. These results indicate that the novel strategy of DRAE is valid for the synthesis of other transition metal doped ZnSe materials.