Structural, Optical, Dielectric, and Electrical Properties of Al: SnO 2 Thin Films via Sol‐Gel Spin Coating

Abstract The aluminium‐doped tin oxide thin film was successfully prepared using the sol‐gel spin coating technique. The XRD pattern shows a tetragonal rutile structure with an average crystallite size of 20 ± 2 nm. FESEM analysis gives the surface morphology of the prepared thin film with an average particle size of 22 nm. EDAX analysis reveals that the elemental composition of the prepared thin films contains tin, oxygen, and aluminium. AFM analysis shows that the surface roughness was very low, and the obtained value is 0.053 µm. UV‐visible analysis shows that the transmittance was high. The optical band gap value is 3.73 eV. The refractive index obtained is 2.26 and is comparable to the bulk value. The real and imaginary values of the dielectric constants were calculated. PL emission spectra show that aluminium‐doped tin oxide thin film shows a broad, high‐intensity peak starting from 360 nm and ending at 421 nm, and a small peak at 358 nm. The small intensity emission peaks at 444 nm represent the violet emission, and 535 nm represents the green emission. Electrical studies reveal that the prepared thin film was n ‐type conducting with an electrical conductivity of 294.56 Ω −1 m −1 . Sheet resistance and Fermi energy of the prepared samples were calculated. The figure of merit value of the aluminium‐doped tin oxide thin film was 1.54 × 10 −6 . All these values make the prepared thin film suitable for several optoelectronic applications.