Improved electronic structure prediction of chalcopyrite semiconductors from a semilocal density functional based on Pauli kinetic energy enhancement factor

The correct treatment of d electrons is of prime importance in order to predict the electronic properties of the prototype chalcopyrite semiconductors. The effect of d states is linked with the anion displacement parameter u, which in turn influences the bandgap of these systems. Semilocal exchange-correlation functionals which yield good structural properties of semiconductors and insulators often fail to predict reasonable u because of the underestimation of the bandgaps arising from the strong interplay between d electrons. In the present study, we show that the meta-generalized gradient approximation (meta-GGA) obtained from the cuspless hydrogen density (MGGAC) [Phys. Rev. B 100, 155140 (2019)] performs in an improved manner in apprehending the key features of the electronic properties of chalcopyrites, and its bandgaps are comparative to that obtained using state-of-art hybrid methods. Moreover, the present assessment also shows the importance of the Pauli kinetic energy enhancement factor, α=(τ-τ<W>)/\τ<unif> in describing the d electrons in chalcopyrites. The present study strongly suggests that the MGGAC functional within semilocal approximations can be a better and preferred choice to study the chalcopyrites and other solid-state systems due to its superior performance and significantly low computational cost.

First-Principles Study of ZnIn2Te4 and HgIn2Te4 Defect-Chalcopyrite Semiconductors Under Different Pressures: Electronic, Elastic, And Optical Properties

First-principle calculations of electronic, elastic, and optical properties for ZnIn2Te4 and HgIn2Te4 defect-chalcopyrite semiconductors have been performed using local density approximation (LDA). Computed energy bandgaps are 1.398 eV and 1.101 eV, respectively, for ZnIn2Te4 and HgIn2Te4, which show the indirect bandgaps behavior. Elastic parameters and Debye temperature have also been investigated at 0, 5, 10, 13, and 14 GPa pressures. Calculated results indicate that both semiconductors are covalent in nature at 0 GPa and become ionic afterward. Optical parameters have also been examined under 0, 5, 10, and 13 GPa in the energy span of 0 eV to 15 eV. The calculated values indicate that these semiconductors are mechanically stable up to 13 GPa and become unstable at 14 GPa. The Calculated values of all parameters are compared with the available experimental and reported values at 0 GPa. A reasonable agreement has been obtained between them. The values of these parameters at 5, 10, 13, and 14 GPa pressures are reported for the first time.

Effect of the Properties of Chalcopyrite Semiconductors on the Physical and Optical Parameters of Cell Layers with CIGS

In this paper, the impact of various buffers of applying components on the effectiveness of CuInGaSe2 solar cells is studied numerically. The SCAPS software is employed to achieve the investigation. The main parameters of the inspected devices are: the photovoltaic conversion effectiveness (η), the filling factor (FF), short-circuit current (Jsc), and open circuit voltage (Voc). These photovoltaic parameters are analyzed vs. the thickness in the various buffer layers under study. The numerical findings revealed that the most significant conversion effectiveness (23.4%) of the CIGS solar cell is obtained with the CdS buffer layer. An attempt is conducted to improve this efficiency by using the SCAPS and by optimizing the two electrical and technological parameters of the three layers (ZnO, CdS, CIGS).

Electronic and elastic properties of AIIB2IIIC4VI defect-chalcopyrite semiconductors

The electronic and elastic properties of [Formula: see text] defect-chalcopyrite semiconductors have been studied using first-principle density functional theory (DFT) calculations. The lattice constants, energy band gap, elastic stiffness constants, bulk modulus, shear modulus, shear anisotropy factor, Young’s modulus, Debye temperature, Poisson’s ratio and B/G ratio have been computed. The values of elastic constants of 14 defect-chalcopyrites and Debye temperature for 18 compounds have been reported for the first time. The obtained results are in reasonable agreement with the experimental values in few cases where experiments are performed and reported values.