Effect of the Cu plasma density on ZnO:Cu thin films grown by PLD

ZnO:Cu thin films were deposited on Si (100) substrates at room temperature by the simultaneous laser ablation of Zn and Cu targets. The plasma parameters (mean kinetic energy (Ek) and density (Np)) were calculated using the time of flight curves obtained from Langmuir planar probe measurements and used as control parameters for the deposition process. In order to change the Cu content incorporated into the films, Np-Cu was varied while keeping Ek-Cu constant. On the other hand, Zinc plasma parameters were both kept constant. The main purpose of this research was to study the effect of combining Zn and Cu plasmas on the optical and structural properties of ZnO:Cu films. Additionally, the effect of a hydrothermal annealing using deionized water as a heterogeneous medium was investigated. XRD results showed a growth in the (101) orientation for all samples. Crystallinity in samples is influenced by plasma density from Cu target (Np-Cu), containing Cu+1 and Cu+2 ions. XRD and PL suggest a Cu+1 incorporation in films grown at intermediate plasma density.