Modeling of Structure, Thermodynamic Properties and Phase Transition Temperaturesof II-VI Crystals

Authors T.O. Parashchuk

Ivano-Frankivsk National Medical University, 2, Halytska St., 76018 Ivano-Frankivsk, Ukraine

Issue Volume 8, Year 2016, Number 2
Dates Received 20 February 2016; published online 21 June 2016
Citation T.O. Parashchuk, J. Nano- Electron. Phys. 8 No 2, 02010 (2016)
DOI 10.21272/jnep.8(2).02010
PACS Number(s) 05.70.Ce, 31.15.Bu
Keywords Cluster models, Quantum chemical calculations (2) , Chalcogenide crystals, Thermodynamic parameters.
Annotation The work is devoted to the theoretical calculations and experimental study of important thermodynamic parameters of II-VI crystals. Cubic sphalerite and hexagonal wurtzite cluster models of polymorphs for stoichiometric II-VI crystals (ZnX, CdX; X = S, Se, Te) have been proposed. In the work one carried out the calculations of thermodynamic parameters under normal conditions and defined the analytical expressions of temperature dependences for energy ΔE, enthalpy ΔH, Gibbs free energy ΔG, entropy ΔS for sphalerite phase stoichiometric crystals of zinc and cadmium chalcogenides. Using the results of DFT-calculations according to equality of Gibbs free energy for sphalerite and wurtzite phases (ΔGS = ΔGW) of zinc chalcogenides crystals we defined phase transition "sphalerite-wurtzite" temperatures, which decreased in the line ZnS (1454 K) – ZnSe (1427 K) – ZnTe (1382 K) and was found the specified region of stability for these polymorphs.

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