Electronic and Band Structure calculation of Wurtzite CdS Using GGA and GGA+U functionals

Abstract

The wurtzite (wz) structure of CdS is analysed using density functional theory within the generalized gradient approximation (GGA) and Hubbard correction (GGA+U). The total energy convergence evaluation is carried out concerning energy cut-off (ecutwfc) and k-point sampling. The geometry optimization of wz-CdS is calculated using the total energy and force minimization process, which is based on the Broyden-Fletcher-Goldfarb-Shanno (BFGS) optimization algorithm. Bulk modulus and lattice parameters are estimated to ensure accuracy of the calculations. The electronic band structure, density of states (DOS), and projected density of states (PDOS) of wz-CdS are analysed. The band structure calculation shows CdS as direct band gap semiconductor. The electronic correlation in CdS is altered by varying U-parameters of valence orbitals of Cd and S. The alteration of electronic correlation results in convergence of the band gap to the experimental value 2.4 eV. The alteration of U-parameter affects substantially the density of states near the band edges.

Facile Synthesis of Barium-Doped Cadmium Sulfide Quantum Dots for the Treatment of Polluted Water: Experimental and Computational Investigations

“…The electronic structure of Ba near the (11−20) surface is investigated, where the densities of states (DOS) are computed and shown in Figure 8 for different concentrations. As shown in Figure 8a, HSE06 calculation results of the DOS plot and the band structure (not shown here) for the pure CdS surface with the band structure reported in previous theoretical works 54 can be found in the form of a direct band gap at the Γ-point. It is observed that the highest occupied state of the CdS surface is mainly derived from the S 3s states, while the lowest unoccupied state is generated from the Cd 5s and Cd 4p states.…”

Induced dipole moments in amorphous ZnCdS catalysts facilitate photocatalytic H2 evolution

“…When the U eff values of Zn and Cd were higher than 7.0 and 4.0 eV, the bandgap ZnCdS trends to be stable. Therefore, the Coulomb interaction U eff values were set to 7.0 and 4.0 eV to describe the 3 d electrons of Zn and 4 d electrons of Cd, respectively, which are also consistent to the literature 64 , 65 .…”

Plant-Based Phytochemicals for Synthesis of Z-Scheme In2O3/CdS Heterostructures: DFT Analysis and Photocatalytic CO2 Reduction to HCOOH and CO

“…However, the PBE functional’s bandgap estimation was lower than the experimental values. To improve the accuracy, GGA+U was applied in the DFT calculation, introducing the Hubbard-U parameter to Cd-d and S-p orbitals for CdS and In-d for In 2 O 3 . , The CdS lattice parameters are 5.88 Å (JCPDF database:00–001–0783), while those for In 2 O 3 are 10.17 Å (JCPDF database: 00–001–0929). To minimize lattice mismatch between CdS and In 2 O 3 surfaces, a 1.73 × 1 supercell for CdS with lattice parameters of 10.17 Å, matching with In 2 O 3 surface lattice, was utilized by using VESTA software .…”

“…However, the PBE functional's bandgap estimation was lower than the experimental values. To improve the accuracy, GGA +U was applied in the DFT calculation, introducing the Hubbard-U parameter to Cd-d and S-p orbitals for CdS and In-d for In 2 O 3 36,37. The CdS lattice parameters are 5.88 Å (JCPDF database:00−001− 0783), while those for In 2 O 3 are 10.17 Å (JCPDF database: 00−001− 0929).…”