Eu <sup> 3 + </ Sup>, Li <sup> + </ Sup> Doped Zno Thin Film Structure And Nature Study

Emitting light is a process that the substance gives out energy after absorbing radiation in some way. Solid-state light sources (light emitting diodes, LEDs) are considered one of the most potential high-tech areas in the 21st century. Rare earth ion Eu3+is a good red luminescence center, and its excitation spectrum peak is at about 395nm, Li+ions act as the low compensation charge and luminescence sensitizer. In this dissertation, Eu rare earth was doped into the ZnO matrix as the separate luminescence center by the pulse laser deposition method, and the crystal structure and optical properties of the films were studied.ZnO:Eu3+, Li+/Si films were prepared on silicon substrates under the substrate temperature of 400℃by PLD technology at different oxygen pressures. The crystal structure and optical properties were studied with the X-ray diffractometer and fluorophotometer. By the X-ray diffraction, it can be seen that the ZnO:Eu3+, Li+films are highly c-axis oriented. In the XRD spectrum, no other crystal orientations are observed except the ZnO crystal orientation, which indicates that the doping elements of Eu3+and Li+have incorporated into the crystal lattice of ZnO, and conform the wurtzite structure with Eu3+as its luminescence centre. When irradiated under the wavelength of 395nm, obvious emission at the wavelength of about 594 nm,613 nm from the rare-earth element of Eu3+can be observed in the photoluminescence spectra.Eu3+,Li+co-doped ZnO films were prepared under different substrate temperature with the 2X10-1 Pa oxygen partial pressure. The XRD spectrum and PL spectrum at room temperature were measured. The results show that rare earth ions can be effectively coped into the ZnO crystal, and the single crystal films are of high c-axis. When the temperature was low, the Eu3+ emission peak could not be observed under the excitation light of 325 nm wavelength, there were not effective energy transfer between ZnO matrix and the doped Eu3+ions; while the temperature was high, the Eu3+emission peak appeared under the 325 nm wavelength excitation in the PL spectra. It can be concluded that the rare earth ions of Eu3+can obtain sufficient transferring energy to enter the ZnO crystal lattice which is helpful for the energy transfer from ZnO matrix to the rare ions.When the doping concentration of Eu3+,Li+in the ZnO matrix decreases, the intensity of the Eu3+intrinsic luminescence peak in the PL spectra increases under the same conditions. That may be because when the concentration exceeds a critical value, the quenching occurs to some extent.