Structural, Energetical and Electronic Properties of CdO and Cd_xZn_1-xO Compounds

We have studied the structural, energetical, and electronic properties of CdxZn1 -xO films in wurtzite structure and CdO in rocksalt, zinc blende, and wurtzite structures by the method of total energy plane-wave expansion with first-principles ultrasoft pseudo-potential technology based on the density functional theory (DFT). Stabilities of CdO in different structures were analyzed and it was concluded that rocksalt and wurtzite structures of CdO almost had the same stability, but the zinc blende structure was not so stable. From the simulation of CdxZn1-xO films, we obtained the equilibrium lattice constants, the formation energies, and the band gap energy bowing parameter. The results of formation energies revealed that the CdxZn1-xOfilms were unstable at the composition of about x=0.4. Phase segregation between ZnO and CdO might occur at this point.