Synthesis and microstructure of NiTe^sub 2

This paper reports on the microstructure of NiTe2 samples grown with different concentrations of Te and thermal gradient. Large crystals were obtained through a self-flux method. Two phases were identified within the Ni-Te system and their stoichiometries determined using scanning electron microscopy with energy dispersive spectroscopy and X-ray diffraction. For the sample synthesized without tellurium excess, the compound was found to have a CdI2 -type structure (space group P-3m1) with unit cell parameters a = b = 3.8581(2) Å and c = 5.2644(3) Å. From SEM and X-ray, it was found that the volume of NiTe2 phase prepared without Te excess and thermal gradient increased in relation to that obtained by employing other methods. Also, the microstructure of the grain boundaries was examined using SEM and crystals rich in Ni were also observed in samples prepared without thermal gradient.