Europium Doped Zinc Oxide Thin Films Grown by Pulsed-Laser Deposition

Wei Lon Wei^1*, Yu-Tso Liao¹, Hung-Lin Lin¹, Fang-Yuh Lo¹, Ming-Yau Chern²

¹Physics, National Taiwan Normal University, Taipei, Taiwan
²Physics, National Taiwan University, Taipei, Taiwan

* Presenter:Wei Lon Wei, email:killyoufirst3007@gmail.com

Eu-doped ZnO thin films (Eu:ZnO) were deposited on c-oriented sapphire substrates under O₂ partial pressure of 3×10^-1 mbar at the substrate temperature of 525°C by using pulsed-laser deposition (PLD). The doping concentrations were from 0.5 to 4 atomic percent. X-ray diffraction (XRD), atomic force microscopy (AFM) were utilized to study structural properties. Photoluminescence (PL) was performed to characterize the optical properties of the thin films. Magneto-optical Faraday effect (MOFE) measurements were applied to obtain magnetic and magneto-optical properties of the thin films.
XRD revealed no secondary phases, and with increasing Eu content, lattice constant decreases from 5.21 to 5.16 Å and crystallite size decreases from 633 to 334 nm. The morphology of Eu:ZnO show round grains and roughness were calculated. Defects such as oxygen, zinc interstitials, and zinc vacancies were identified from PL spectra for all Eu-doped ZnO thin films. In addition, emission lines from 4f-4f transitions of Eu³⁺ were also detected. MOFE spectra show strong response at wavelengths between 300 and 390 nm, and paramagnetism of the thin films.

Keywords: PLD, XRD, AFM, PL, MOFE