Correlation between surface topography, optical band gaps and crystalline properties of engineered AZO and CAZO thin films

In this work, the stereometric 3-D surface topography as well as the optical properties of the Al doped ZnO (AZO), and Al/Cu co-doped ZnO (CAZO) thin films were investigated. These films were deposited with different thicknesses of 50 and 150 nm. The effect of dopants (Al, Cu) and sputtering parameters on the microstructures, crystalline structures, and fractal features were probed by Atomic Force Microscopy (AFM), X-ray diffraction, and Rutherford back scattering. AFM analysis of 3-D surface texture provided a deeper insight into their characteristics and implementation in graphical models and computer simulation. Studying surface roughness of samples at nanometer scale revealed a fractal structure which confirmed the relationship between the value of the fractal dimension and surface roughness parameters. Moreover, the optical properties of AZO and CAZO thin films and the relationship between their optical band gaps and their varied thicknesses were evaluated by Ultraviolet-visible spectrophotometry.