Electronic structure and optical properties ofZnX(X=O,S, Se, Te): A density functional study

Abstract

Electronic band structure and optical properties of zinc monochalcogenides with zinc-blende-and wurtzite-type structures were studied using the ab initio density functional method within the LDA, GGA, and LDA+U approaches. Calculations of the optical spectra have been performed for the energy range 0-20 eV, with and without including spin-orbit coupling. Reflectivity, absorption and extinction coefficients, and refractive index have been computed from the imaginary part of the dielectric function using the Kramers-Kronig transformations. A rigid shift of the calculated optical spectra is found to provide a good first approximation to reproduce experimental observations for almost all the zinc monochalcogenide phases considered. By inspection of the calculated and experimentally determined band-gap values for the zinc monochalcogenide series, the band gap of ZnO with zinc-blende structure has been estimated.

Role of diatomic hydrogen in the electronic structure of ZnO

“…Refs. [35][36][37] shows that the calculated band parameters can be more within reasonable limit for U=6 eV and J=1 eV.…”

“…The problem has partially been solved [35][36][37] by using the GGA +U, 33,34 which requires explicit values of the parameters U and J are required as input.…”

Strain-induced modulation of band structure of silicon

“…in the close vicinity of the band extremum in the energy range 25-300 meV 28 . As it was demonstrated for a number of III-V and II-VI semiconductors, the LDA calculations underestimate not only the band gap, but also the CB effective masses.…”

“…The convergence criteria and more details about the optical calculations were discussed in Ref. 28 .…”

Similarity of electronic structure and optical properties of Mg 2 NiH 4 and Si

“…The convergence criteria and more details about the optical calculations were discussed in Ref. 15 . Effective density of states (DOS) and DOS masses have been calculated from the total DOS (TDOS)…”