Calculation of the Band Structure for GaAs and ZnTe Nanoparticles from the Density Functional Theory Based on LDA, GGA and HSE06

The energy band structure and density of state (DOS) are calculated using density functional theory (DFT) for GaAs and ZnTe semiconductors for both the bulk and nanoparticles (NPs) and implemented in the CASTEP code. The calculations are employed within the local density approximation (LDA), generalized gradient approximation (GGA), and hybrid functionals of Heyd-Scuseria-Ernzerh of (HSE06). The DFT results within both LDA and GGA give lower values of band gap energies, while the HSE06 yields good results relative to the experimental data. Thus, HSE06 is employed to study the effect of size on band structures of semiconductor NPs. The results presented here illustrated that band gap increases with the reduction of NPs size due to the increase in lattice parameters.