Tuning the optical and electrical properties of magnetron-sputtered Cu-ZnO thin films using low energy Ar ion irradiation

Cu doped ZnO (Cu-ZnO) nanocomposite thin films were successfully synthesized at room temperature by RF magnetron sputtering. The signature of Cu in pristine ZnO thin films was confirmed by Rutherford Backscattering Spectroscopy (RBS) with atomic concentration of similar to 10%. The Cu-ZnO thin films were irradiated with 800 keV Ar ion beam at three different ion fluences viz. 5 x 10(15), 7 x 10(15) and 9 x 10(15) ions/cm(2). As characterized by X-ray diffraction, the pristine and irradiated films show a hexagonal wurtzite structure with remarkable intensities of (100), (002) and (101) orientations. The surface morphology of the pristine and irradiated films was recorded using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The images clearly show the grain growth near the surface of films with increasing the ion fluences. The surface plasmon absorption (380 nm onwards) indicating the formation of metal nanoparticles in oxide matrices was confirmed by UV-visible spectroscopy of ion irradiated films. The electrical properties of the pristine and irradiated films were deduced by current voltage (I-V) and Hall measurements. The conductivity of the film increases as irradiation proceeds, achieves a maxima and then decreases with further processing of the ion beam. This study explores ion beam irradiation as a versatile tool to tailor the physical properties of nanocomposite thin films. Further, the properties can be precisely controlled by optimizing ion fluences and incident ion energy as well.

Automated summary

Cu-doped ZnO nanocomposite thin films were synthesized by RF magnetron sputtering at room temperature, and irradiated with Ar ion beam at different fluences to tailor their physical properties. The study shows that ion beam irradiation can effectively modify the crystal structure and electrical properties of the films, providing a versatile tool for surface modification.