RETRACTED: Growing crystals and studying structure and electronic properties of Cu2ZnGe(SхSe1-x)4 compositions
I. V. Bodnar, В. В. Хорошко, Veronika A. Yashchuk, В. Ф. Гременок, Mohsin Kazi, Mayeen Uddin Khandaker, Abdul Ghafoor Abid, T.I. Zubar, Д.И. Тишкевич, А.В. Труханов, Sergei V. Trukhanov
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.