Publications (3)2.29 Total impact
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Article: Effect of cadmium oxide incorporation on the microstructural and optical properties of pulsed laser deposited nanostructured zinc oxide thin films
Material chemistry and physics, 121( 2010), 406-413. 01/2010; -
Article: Effect of cadmium oxide incorporation on the microstructural and optical properties of pulsed laser deposited nanostructured zinc oxide thin films
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ABSTRACT: CdO doped (doping concentration 0, 1, 3 and 16 wt%) ZnO nanostructured thin films are grown on quartz substrate by pulsed laser deposition and the films are annealed at temperature 500 °C. The structural, morphological and optical properties of the annealed films are systematically studied using grazing incidence X-ray diffraction (GIXRD), energy dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), atomic force microscopy (AFM), Micro-Raman spectra, UV–vis spectroscopy, photoluminescence spectra and open aperture z-scan. 1 wt% CdO doped ZnO films are annealed at different temperatures viz., 300, 400, 500, 600, 700 and 800 °C and the structural and optical properties of these films are also investigated. The XRD patterns suggest a hexagonal wurtzite structure for the films. The crystallite size, lattice constants, stress and lattice strain in the films are calculated. The presence of high-frequency E2 mode and the longitudinal optical A1 (LO) modes in the Raman spectra confirms the hexagonal wurtzite structure for the films. The presence of CdO in the doped films is confirmed from the EDX spectrum. SEM and AFM micrographs show that the films are uniform and the crystallites are in the nano-dimension. AFM picture suggests a porous network structure for 3% CdO doped film. The porosity and refractive indices of the films are calculated from the transmittance and reflectance spectra. Optical band gap energy is found to decrease in the CdO doped films as the CdO doping concentration increases. The PL spectra show emissions corresponding to the near band edge (NBE) ultra violet emission and deep level emission in the visible region. The 16CdZnO film shows an intense deep green PL emission. Non-linear optical measurements using the z-scan technique indicate that the saturable absorption (SA) behavior exhibited by undoped ZnO under green light excitation (532 nm) can be changed to reverse saturable absorption (RSA) with CdO doping. From numerical simulations the saturation intensity (Is) and the effective two-photon absorption coefficient (β) are calculated for the undoped and CdO doped ZnO films.Materials Chemistry and Physics. -
Article: Influence of europium oxide doping on the structural and optical properties of pulsed laser ablated barium tungstate thin films
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ABSTRACT: Nanostructured Eu2O3 doped Barium tungstate (BaWO4) crystallites are successfully synthesized using pulsed laser deposition (PLD) technique. The influence of different Eu2O3 doping concentrations (1,2,3 & 5 wt.%) on the structural, surface morphological and optical properties are systematically studied using XRD, micro-Raman, SEM, AFM, UV–vis and photoluminescence spectroscopy. All the films are polycrystalline with tetragonal scheelite structure. The vibrational analysis of the atoms in BaWO4 is studied by micro-Raman spectra using factor group analysis. The surface morphological analysis by SEM and AFM reveals the presence of fine nanoparticles with distinct grain boundaries in all the films. The band gap energy variation in the Eu2O3 doped BaWO4 films is in accordance with the variation of the sizes of nano particles in the films. The films with higher Eu3+ doping concentrations (≥2 wt.%) show a PL emission peak centered around 614 nm when excited at 394 nm which can be attributed to the 5D0 → 7F2 (0–2) transition of Eu3+ ion.Research highlights▶ Study on the influence europium oxide doping on the structural and optical properties of laser ablated barium tungstate thin films is new. ▶ The surface morphological analysis by SEM and AFM reveals the presence of fine nanoparticles with distinct grain boundaries in all the films. ▶ The films with higher Eu3+ doping concentrations (≥2 wt.%) show a PL emission peak centered around 614 nm when excited at 394 nm which can be attributed to the 5D0 → 7F2 (0–2) transition of Eu3+ ion ▶ The observation of PL emission in these films is a new result which can have large practical applications and also it shows that BaWO4 can act as host material for europium ion. ▶ Detailed analysis of the Raman spectra of BaWO4 films are presented.Journal of Alloys and Compounds 509(6):2745-2752. · 2.29 Impact Factor
