Characterization of Eu doped ZnO micropods prepared by chemical bath deposition on p-Si substrate

The chemical bath deposition method was used to synthesize Eu-doped ZnO on p-type (100) silicon. The SEM image shows the formation of micropod-like ZnO. EDX and XPS measurements showed an increase in the Eu concentration up to 2.54% and the simultaneous presence of Eu³⁺ and Eu²⁺. XRD analysis confirmed that the interstitial Eu³⁺ ions distorted the four tetrahedral bonds, and the substitution of Eu²⁺ ions increased the c lattice parameter. Only Eu^{3+ 5}D₀→⁷F₂ transition-related emission was observed, so a weak transfer energy from the ZnO matrix to the Eu ion occurred. However, the competition between the emission of deep-level defects in the host matrix and that of Eu³⁺ ions deforms the visible emission towards the red color. The I–V measurements of the Eu-ZnO/p-Si heterojunctions showed diode-like behavior with a low rectification ratio and a barrier height around 0.84 eV not affected by the Eu concentration.