Initio Study of Electronic , Structural , Thermal and Mechanical Characterization of Cadmium Chalcogenides 65

Based on Density Functional Theory, we have applied Full Potential Augmented Plane Wave plus local orbital method (FAPW+lo)to study the electronic, structural, optical, thermal and mechanical properties of some semiconducting materials. In this paper we discuss the Zinc blende, CdX (X = S, Se and Te) compounds with the fullpotential linear-augmented plane wave (FP-LAPW) method within the framework of the density functional theory (DFT) for electronic, structural, thermal and mechanical properties using the WIEN2k code. For the purpose of exchangecorrelation energy (Exc) determination in Kohn–Sham calculation, the standard local density approximation (LDA) formalism is utilized. Murnaghan’s equation of state (EOS) is used for volume optimization by minimizing the total energy with respect to the unit cell volume. The calculated lattice parameters and thermal parameters are in good agreement with other theoretical calculations as well as available experimental data. Introduction. Cadmium Chalcogenides family is one of the II-VI wide band gap compound semiconductors. In that family CdS, CdSe and CdTe are some of the main materials. These materials have variousscientific applications, such as solar cells, high efficiency thin film transistors, high density optical memories, light emitting diodes, laser diodes, photovoltaic devices, etc. The recentinnovation of the blue-green laser diode based on the CdX compounds has changedconsideration in their physical properties. CdX compounds are having different phases or crystal structures (Zinc blende, wurtzite). For our convenience we have preferred the zinc blende phase for all three compounds. Because this structure has fewer atoms in unit cell so it is easier for computational treatment. In fact for CdTe, the zinc blende structure is the standard crystal structure or phase, but for the other two compounds CdS and CdSe have wurzite phase. In the past decades numerous experimental and theoretical investigations were carried out for CdX. Many computational methods based on DFT [1]have been studied. But the calculations carried out by using conventional DFT produce disagreeable electronic properties. There is a big variance between experimentally calculated and theoretical data. The variation in energy gap is completely based on the method to calculate the band structure. Some theoretical reports are in good agreement with the measured one. They were calculated based on Local Density Approximation (LDA). The modern ab-inito calculation solves the discrepancies. We have used FP-LAPW+lo to calculate the band structure. The band structure of CdX binary compounds have been calculated by using Full Potential Linearized Augmented Plane Wave method Plus local orbits (FP-LAPW+lo) within the Generalized Gradient Approximation (GGA). There are several methods and theoretical reports available to calculate the band structure and optical properties but some controversies are at there. But the FP-LAPW+lo gives the closer values with the experimental data.In this paper we have presented the structural, elastic, electronic and thermal properties of CdX binary compounds. FP-LAPW+lo is the method used to © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/