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We have determined the stable structures of AuCu_n, Au₂Cu_n, Au₃Cu_n and Au_xCu_8-x clusters. It has been observed that AuCu_n, Au₂Cu_n and Au₃Cu_n systems have two-dimensional (2D) structures up to six atoms and they become three-dimensional (3D) afterwards. Au_xCu_8-x clusters favor 3D structures till the Au₇Cu₁ cluster. We have found a lowest energy isomer of Au₆Cu₂ from the literature. Bond lengths, binding energies, density of states (DOS), highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO-LUMO) gaps, ionization potential (IP) and electron affinity (EA) have been calculated for these structures using the first principles density functional theory (DFT) within the generalized gradient approximation (GGA) and the local density approximation (LDA). Generally, we have observed the overlap between s electrons of Cu and p electrons of Au near the Fermi level. Charge transfers are calculated by using the Löwdin analysis. It is observed that one Cu atom does not significantly modify the clusters which have more gold atoms. It is also seen that these clusters generally have nonmagnetic properties and results are consistent with the hybridization between s and d orbitals of Au in Au_xCu_8-x clusters.

In this work, we have synthesized ZnO:Al thin films by pulsed laser deposition technique and investigated their microstructural and optical properties. The XRD study confirmed a polycrystalline structure of wurtzite ZnO in all films. Further, Al doping has improved the crystallinity and decreased the crystal size and volume of the unit cell. The surface morphology was homogeneous with nanoscopic crystals clustered to form granular nanoparticles. The optical properties significantly improved by increasing the Al doping concentration. The produced thin films are excellent candidates for use as an anti-reflection layer in solar cells due to their outstanding properties.