Influence of Boron Doping on the Structural, Morphological, and Optical Properties of Nanostructured CdO Thin Films Synthesized by Chemical Spray Pyrolysis

This study explores the influence of boron doping on the structural, morphological, and optical characteristics of nanostructured cadmium oxide (CdO) thin films fabricated using chemical spray pyrolysis (CSP). XRD analysis confirmed the polycrystalline nature of the films, with the (200) plane as the dominant orientation. the incorporation of boron led to a noticeable increase in crystallite size, rising from 11.21 nm for pure CdO to 15.79 nm for films doped with 3% boron, reduced dislocation density (85.04 × 10¹⁴ to 61.65 × 10¹⁴ lines/m²), and decreased lattice strain (34.53 × 10⁻⁴ to 25.38 × 10⁻⁴). Atomic force microscopy (AFM) revealed a reduction in surface roughness (9.69 nm to 4.25 nm) and particle size (79.03 nm to 60.49 nm) with doping. Optically, transmittance decreased from 94% (pure CdO) to lower values with boron content, while the absorption coefficient increased (5.1 × 10⁴ cm⁻¹ to 5.65 × 10⁴ cm⁻¹). The optical bandgap narrowed from 2.76 eV to 2.64 eV, while the refractive index and extinction coefficient exhibited a reduction as well.