Violet–blue luminescence from hafnium oxide layers doped with CeCl₃ prepared by the spray pyrolysis process

Abstract

Abstract HfO 2 :CeCl 3 coatings were deposited by the spray pyrolysis method employing hafnium dichloride oxide and CeCl 3 dissolved in deionized water (18 MΩ/cm). The room temperature photoluminescence characteristics of the HfO 2 :CeCl 3 films were studied as a function of the deposition parameters such as doping concentrations and substrate temperature. The presence of two different Ce 3+ centres in HfO 2 is detected from photoluminescence measurements. A reduction of the luminescence intensity is observed with an increase of both the CeCl 3 concentration and the deposition temperature. X‐ray diffraction measurements of these films showed that the crystalline structure depends on the substrate temperature. For substrate temperatures less than 350 °C the deposited films are almost amorphous, while substrate temperatures higher than 400 °C produce diffraction peaks corresponding to the monoclinic phase of HfO 2 . The chemical composition of the films as determined by energy dispersive spectroscopy is also reported. Furthermore, the surface morphology characteristics of the coatings, as a function of the deposition temperature, are also presented. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)