Synthesis, structural, X-ray photoelectron spectroscopy (XPS) studies and IR induced anisotropy of Tl4HgI6 single crystals

Abstract

In the present work, we report on the synthesis and structural properties including X-ray protoelectron spectroscopy (XPS) analysis of Tl4HgI6 crystals that were grown by Bridgman-Stockbarger method up to 80 mm in length and 18 mm in diameter. The existence of the ternary compound Tl4HgI6 that melts incongruently at 641 K was confirmed. Phase equilibria and structural properties for the TlI–HgI2 system were investigated by differential thermal analysis (DTA) and X-ray diffraction (XRD) methods. X-ray photoelectron spectra were measured for both pristine and Ar+ ion-bombarded Tl4HgI6 single crystal surfaces. The data reveal that the Tl4HgI6 single crystal is sensitive with respect to Ar+ ion-bombardment as 3.0 keV Ar+ irradiation over 5 min at an ion current density 14 μA/cm2 induces changes to the elemental stoichiometry of the Tl4HgI6 surface, leading to a decrease of the mercury content in the topmost surface layers. X-ray photoelectron spectroscopy (XPS) measurements indicate very low hygroscopic nature of the Tl4HgI6 single crystal surface. The IR coherent bicolor laser treatment at wavelengths 10.6/5.3 μm has shown an occurrence of anisotropy at wavelengths 1540 nm of Er:glass laser. This may open the applications of Tl4HgI6 as a material for IR laser triggering.