SAIP 2011 Support
Optical properties of SrGa2S4:Ce3+ films prepared by pulsed reactive cross laser beam ablation method (PRCLA)
Presented by Ms. Pulane MOLEME on 13 Jul 2011 from 17:00 to 19:00
Type: Poster Presentation
Track: Track A - Condensed Matter Physics and Material Science
<p>SrGa<sub>2</sub>S<sub>4</sub>:Ce<sup>3+</sup> thin films are promising for full colour thin-film electroluminescent (EL) and field emission displays (FED’s) because of its good optical properties. These films were previously prepared using several different techniques such as sputtering (RF), molecular beam epitaxy (MBE), reactive multi-source deposition (MSD), metal-organic chemical vapour deposition (MOCVD), deposition from binary vapours (DBV) and Pulsed Laser Deposition (PLD). In the present study, Ce doped SrGa<sub>2</sub>S<sub>4</sub> thin films were prepared for the first time using pulsed reactive cross laser ablation (PRCLA) technique. Characterization of the films was carried out with scanning electron microscopy (SEM), atomic force microscopy (AFM) and x-ray diffraction (XRD). Cathodoluminescence (CL) and photoluminescence (PL) measurements were taken with a S2000 Ocean Optics Spectrometer and a Varian Cary Eclipse Fluorescence Spectrophotometer respectively. The substrate temperature, number of pulses and the working pressure are the parameters that were varied during the preparation of the thin films. A single-phase SrGa<sub>2</sub>S<sub>4</sub> layer with high crystallinity was obtained at the growth temperature of 400<sup>o</sup>C. XRD patterns also showed that the properties of the films are relatively sensitive to substrate temperature. PL showed one broad band that can fit two Gaussian peaks according to the two Ce<sup>3+</sup> emission peaks which are known to originate from radiative transitions from 5d (T<sub>2g</sub>) → 4f (<sup>2</sup>F<sub>5/2</sub>) and from 5d (T<sub>2g</sub>) → 4f ((<sup>2</sup>F<sub>7/2</sub>) respectively. CL showed two broad emission peaks around 441nm and 478nm which are due to Ce<sup>3+</sup> transitions. The AFM images of the films prepared had a rough surface, which became smooth after annealing in vacuum at 700<sup>o</sup>C temperature. Non-uniformity in particles of the films and rough surface were observed from the SEM images.
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