eV . The XPS chamber was used to carry out ultraviolet photoelectron spectroscopy 42 (UPS) measurements, which was done by operating a UV source (21.22 eV) in order to estimate the work function of the material. The film density was measured by X-ray reflectivity (XRR) using Cu Kα radiation with the Cu Kβ filtered off by a nickel filter. An X'Pert MRD diffractometer with 1/32⁰ divergence slit and a 0.27° plate collimator followed by a proportional detector were used to record the data. The measured data were fitted for thickness and density of the films using PANAlytical X'Pert Reflectivity software.