Microstructural, optical, and electrical properties of Eu, Tb co-doped ZnO micropods elaborated by chemical bath deposition on a p-Si substrate

Eu, Tb co-doped ZnO was elaborated by chemical bath deposition on p-type (100) Si and annealed at different temperatures. Micropod morphology was observed using SEM. All samples exhibited a wurtzite structures. The EDX concentrations of Eu and Tb did not exceed 2.1% and 1.3%, respectively. The mixed valence states of Eu and Tb in the ZnO micropods were demonstrated using XPS analysis. Microstructural analysis of the co-doped sample showed variations as a function of the Eu and Tb concentration ratios. The modification of the Pl intensity and center of gravity of the visible band emission is due to the perturbation of native defects that interact with RE ions. The emission of Eu ⁵D₀ → ⁷F₂ (615 nm) and Tb ⁵D₄ → ⁷F₃ (620 nm) in the red-orange region of visible light was obtained at an excitation wavelength of 405 nm. The competition between the effect of annealing temperature and that of the two dopant concentrations is believed to be an effective strategy for changing the color emission of Eu, Tb co-doped ZnO. The CIE color emission of the co-doped sample annealed at 500 °C and X_Eu = 1.19%, X_Tb = 0.92% annealed at 700 °C lies in the white-light region reported in the literature for designing WLED. The Eu, Tb co-doped ZnO/p-Si heterojunction showed good rectifying I–V characteristics, and the electrical parameters were similar to those obtained for each dopant. A significant decrease in series resistance was allowed to the growth of a ZnO seed layer before the formation of ZnO micropods. Graphical abstract: [Figure not available: see fulltext.]