Optical and structural properties of ZnO:Eu thin films grown by pulsed laser deposition

Abstract

Eu doped ZnO thin films were deposited by pulsed laser deposition on fused silica substrate at room temperature and 300 °C in an oxygen ambient of pressure of 10 Pa. The films exhibited a wurtzite structure. The average transmittance exceeded 80% in the visible region confirming a good optical quality of the films. The characteristic emission of both Eu2+ and Eu3+ was observed when indirectly excited. The increase of substrate temperature to 300 °C led to higher crystallites size, lower efficiency of energy transfer from ZnO to Eu ions and lower resistivity of the film. XPS revealed the ratio of Eu divalent and trivalent states as 35%:65% and 27%:73% for sample deposited at room temperature and 300 °C, respectively. AFM showed higher RMS for the sample prepared at 300 °C.