Characterization of tetrahedrite Cu10Cd2Sb4S13 monograin materials grown in molten CdI2 and LiI

Abstract Synthesis of Cd-substituted tetrahedrite Cu10Cd2Sb4S13 (TH Cd) monograin powders are performed by the molten salt synthesis-growth method using two different fluxes: CdI2 and LiI. The X-ray diffraction (XRD) data of the materials indicates that mainly single phase of tetrahedrite Cu10Cd2Sb4S13 compound is formed in both flux salts. XRD pattern of TH Cd crystals grown in LiI reveals a shift of all diffraction peaks, lower CdS content and a smaller lattice parameter values in comparison with those formed in CdI2. Energy dispersive X-ray spectroscopy reveals stoichiometric composition of Cu10Cd2Sb4S13 crystals grown in CdI2 and Cu-poor grown in LiI. Analysis by Atomic Absorption Spectroscopy confirms the incorporation of Li into TH Cd crystals at the level of 6.7 × 1020 at/cm3. The photoluminescence (PL) study of Cu10Cd2Sb4S13 microcrystals at T = 10 K shows single broad asymmetric photoluminescence bands with the maxima at around 1.08 and 1.16 eV for materials grown respectively in CdI2 and LiI. The thermal quenching activation energy of this PL band is EA= 88±6 and 199±7 meV for TH Cd crystals grown in CdI2 and LiI, respectively. Changes in the lattice parameters, composition and shift in PL maximum give evidences of Li incorporation from LiI into the crystal lattice of TH Cd forming Cu10-xLixCd2Sb4S13 solid solution.