Rare earth Eu³⁺ co-doped AZO thin films prepared by nebulizer spray pyrolysis technique for optoelectronics

Rare earth element (i.e.) europium co-doped aluminum zinc oxide (Eu:AZO) thin films were deposited on microscope glass slides by nebulizer spray pyrolysis with different Eu-doping concentrations (0, 0.5, 1, and 1.5%). The deposited films were investigated using X-ray diffraction, AFM, EDAX, FT-Raman, UV–visible, PL, and Hall effect measurements. X-ray confirmed the incorporation of aluminum and europium ions into the ZnO structure. All films have polycrystalline nature with hexagonal wurtzite structure at (002) direction. Topological depictions exhibited minimum surface roughness and low film thickness for pristine AZO thin film. EDAX study authorizes the existence of Zn, O, Al, and Eu in Eu: AZO thin films. Raman spectra exhibited the characteristic of ZnO-wurtzite structure (E₂-high) mode at 447 cm⁻¹. The deposited film showed high optical transmittance of ~90% in visible region, and the direct energy gap was around 3.30 eV for pristine AZO thin film. The PL spectra emitted a powerful UV emission situated at 388 nm, and it indicates that the film has good optical quality. The obtained large carrier concentration and less resistivity values are 4.42 × 10²¹ cm⁻³ and 3.95 × 10⁻⁴ Ω cm, respectively, for 1.5% Eu-doped AZO thin film. The calculated figure of merit value is 17.29 × 10⁻³ (Ω/sq)⁻¹, which is more suitable for the optoelectronic device.