Epitaxial growth and luminescent properties of Eu3+-doped Gd2O3 thin films via chemical solution deposition

• Undoped and Eu 3+ -doped Gd 2 O 3 thin films were epitaxially grown on (100) MgO substrate via CSD method. • The decomposition mechanism of the propionate type precursor was proposed. • Structural and morphological properties vary with europium doping level. • Urbach energy analysis reveals enhanced electronic disorder at higher doping. • PL emission intensifies with Eu 3+ content due to increased emissive center density. • XPS depth profiling shows dopant stabilization below the film surface. • Incorporation of Eu 3+ ions in the Gd 2 O 3 cubic system favours both the epitaxial growth and the luminescence emission. In this work, the chemical solution deposition (CSD) technique has been employed for the first time to grow europium-doped gadolinium oxide (Gd 2 O 3 :Eu 3+ ) epitaxial thin films on (100)-oriented MgO substrates. The influence of Eu 3+ doping levels (1, 2.5, 5 at.%) on the structural, morphological, and optical properties of the films was systematically investigated. Thermal decomposition of the chemical precursors was examined using thermogravimetric analysis (TG-DTA) coupled with mass spectrometry (MS). Fourier transform infra-red (FTIR) spectroscopy was employed to track ligand removal, while phase formation and crystallinity were confirmed by X-ray diffraction (XRD), showing the formation of epitaxial cubic Gd 2 O 3 . Atomic force microscopy (AFM) revealed changes in surface morphology and roughness with increasing Eu content. Optical band gaps and Urbach energies were determined via ultraviolet–visible (UV–Vis) spectroscopy, indicating changes in electronic disorder with doping. X-ray photoelectron spectroscopy (XPS) confirmed the Eu 3+ incorporation and stoichiometry of the films, with depth profiling showing dopant apparent concentration maximum detected after sputtering. Photoluminescence (PL) measurements demonstrated efficient red emission under UV excitation, primarily from the 5 D 0 - 7 F 2 transition of Eu 3+ . This represents the first report of epitaxial growth by CSD of undoped or Eu 3+ -doped Gd 2 O 3 two-dimensional systems demonstrating the versatility of this compositionally tunable synthetic approach.