Characterization of Laser Ablated SrAl<sub>2</sub>O<sub>4</sub>:Eu<sup>2+</sup>, Dy<sup>3+</sup> Thin Films Deposited on the Optimum Substrate Temperature Range

Abstract

The morphological, structural and photoluminescence (PL) of laser ablated SrAl 2 O 4 :Eu 2+ , Dy 3+ thin films deposited on optimum substrate temperature range of 200-500°C are reported. The 200-500°C substrate temperature was considered, since on that range, low cost highly emitting SrAl 2 O 4 :Eu 2+ , Dy 3+ thin films are always produced. The surface morphology analysis of the films was done by using the scanning electron microscopy (SEM) and atomic force microscopy (AFM). The energy dispersive X-ray spectrometer (EDS) was employed for elemental composition analysis. The structural analysis was done by the X-ray diffraction (XRD) technique. The photoluminescence (PL) data collection was done by using Cary Eclipse fluorescence spectrophotometry. The films were excited by the UV light from the xenon lamp. The highest green emission intensity with a peak at 517 nm and highest initial afterglow intensity were recorded by the sample that was deposited at 350°C. The green peak at 517 nm is attributed to 4f 6 5d 1 → 4f 7 Eu 2+ transitions. AFM images with well defined grains were observed on the films deposited at temperatures higher than 200°C. The EDS elemental composition analysis showed that the films consist of all the main elements of SrAl 2 O 4 :Eu 2+ , Dy 3+ , i.e., Al, Sr, O. The changes in the film photoluminescence and morphology with the substrate temperature are discussed.