Abstract
Single crystals of Cu(2)ZnGeSe(4) and Cu(2)ZnGeS(4) solid solutions were developed and successfully obtained using the chemical vapor transfer method, with iodine acting as a transporter. The structure, compositional dependences of lattice parameters, pycnometric and X-ray densities and microhardness were determined. The chemical composition determined by the X-ray microanalysis satisfactorily corresponds to the nominal one with a tolerance of ±5 %. The XRD analysis showed that all the obtained compounds and their solid solutions have unit cell described by tetragonal symmetry. The attice parameters were found to be а = 5.342 ± 0.005 Å, с = 10.51 ± 0.01 Å for the Сu(2)ZnGeS(4) compound and а = 5.607 ± 0.005 Å, с = 11.04 ± 0.01 Å for the Cu(2)ZnGeSe(4), respectively. Structural studies confirmed the validity of the Vegard's law in relation to the obtained samples. The pycnometric densities of ∼4.28 g/cm(3) for the Cu(2)ZnGeS(4) and ∼5.46 g/cm(3) for the Cu(2)ZnGeSe(4) were found to be slightly less than their X-ray densities of ∼4.32 g/cm(3) and ∼5.52 g/cm(3), respectively. The maximum microhardness of ∼398 kg/mm(2) for these solid solutions corresponds to x = 0.60. The melt point of the solid solutions increases from ∼1180 °C for the Сu(2)ZnGeSe(4) up to ∼1400 °C for the Сu(2)ZnGeS(4). Based on X-ray fluorescence analysis and DTA data, the phase diagram of the Cu(2)ZnGeSe(4)-Cu(2)ZnGeS(4) system was constructed. Analysis of the obtained diagram indicates its first type according to Rozbom's classification.