Structure and optical properties of Er 3+ doped ZnSe nanoparticles

ZnSe: x %Er 3+ (0 ≤  x  ≤ 1.8) thin films were deposited on the glass substrates using a photo-assisted chemical bath deposition method. The X-ray diffraction investigation revealed that the samples exhibited a hexagonal crystalline structure. The undoped ZnSe had a crystallite size of 21 nm, which decreased to 4 nm as the concentration of Er 3+ increased. The Scanning electron microscopy images showed that the shape of the particles changed from nanoflakes to glass-like particles after the introduction of Er 3+. The expected elemental composition was determined using energy-dispersive spectroscopy. The ultraviolet–visible spectroscopy analysis revealed that increasing the concentration of Er 3+ modified the band gap energy within the range of 2.75–4.09 eV. The photoluminescence investigation revealed two distinguishable emission peaks at the energy of 1.79 and 2.34 eV when stimulated with an energy of 5.68 eV. These emission peaks were attributed to the presence of impurities in the host material. The Commission Internationale de l’Eclairage revealed that increasing Er 3+ concentration shift the yellow emission from the host towards the light blue region. Incorporating Er³⁺ dopant into the ZnSe lattice significantly alters the structure and optical properties.