CdSxTe1-x ternary semiconductors band gaps calculation using ground state and GW approximations

• The direct Γ- Γ and indirect Γ- X and Γ- L bands gaps show a nonlinear behavior when S content is enhanced.
• The quasiparticle band gap result for the investigated semiconductors is improved using the GW approximation.
• All CdSxTe1-x compounds in all compositions range from 0 to 1 are direct band gap semiconductors.

We present band gap calculations of zinc-blende ternary CdSxTe1-x semiconductors within the standard DFT and quasiparticle calculations employing pseudopotential method. The DFT, the local density approximation (LDA) and the Generalized Gradient Approximation (GGA) based calculations have given very poor results compared to experimental data. The quasiparticle calculations have been investigated via the one-shot GW approximation. The present paper discuses and confirms the effect of inclusion of the semicore states in the cadmium (Cd) pseudopotential. The obtained GW quasiparticle band gap using Cd+20 pseudopotential has been improved compared to the obtained results from the available pseudopotential without the treatment of semicore states. Our DFT and quasiparticle band gap results are discussed and compared to the available theoretical calculations and experimental data.

Band gaps improvement concerning the binary and ternary alloys using the GW approximation and Cd20+ pseudopotential with others levels of approximations (the LDA and GGA approximation employing the Cd12+ and the LDA within Cd20+ pseudopotential).Figure optionsDownload as PowerPoint slide