Structural and Optical Properties of Aluminum Doped Cadmium Oxide (CdO:Al) Thin Film Prepared by Sol-Gel Spin-Coating Method

Aluminum-doped cadmium oxide (CdO:Al) thin films are deposited on silica substrates by thesol–gel spin-coating method as a function of spin coater’s rpm (revolution per minute). Cadmiumacetate dihydrate and Aluminum nitrate have been taken as the precursor material and a sourceof Al-dopant respectively. CdO:Al thin films are characterized by Raman scattering, x-raydiffraction (XRD), Fourier Transform Infrared (FT/IR), Field emission scanning electronmicroscopy (FE-SEM), SEM-EDX, UVvis, AFM, Ellipsometer and Four-point probe. XRDresult indicates the highest crystallinity at 6000 rpm with a crystallite size of 31.845 nm, cubicphase formation, and strain of ~1.6 X10-2. FE-SEM/SEM/EDX shows the well-facetedhomogeneous surface structure at 6000 rpm having the average particle size of 130.05 nm,lowest resistivity of 9X10-8 Ω-cm and the lowest band gap energy of 2.19 eV. FT/IR confirmsthe presence of CdO:Al in the film with the peak position shifting to higher wavenumbers athigher rpm. Raman results indicate that the presence of crystalline phase located at 933.93 cm-1.