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Structural, morphological, optical, and nonlinear optical properties of fluorine‐doped zinc oxide thin films deposited on glass substrates by the chemical spray technique
Author(s) -
Castañeda L.,
MoralesSaavedra O. G.,
Acosta D. R.,
Maldonado A.,
de la L. Olvera M.
Publication year - 2006
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200521386
Subject(s) - materials science , thin film , crystallite , band gap , doping , transmittance , second harmonic generation , substrate (aquarium) , scanning electron microscope , analytical chemistry (journal) , zinc , optics , optoelectronics , nanotechnology , chemistry , composite material , metallurgy , laser , oceanography , physics , chromatography , geology
Fluorine‐doped zinc oxide thin films (ZnO:F) were deposited on sodocalcic glass substrates from an aged solution using a chemical spray technique. The effect of substrate temperature ( T S ) on the morphological, optical, and nonlinear optical (NLO) properties of the ZnO:F thin films was studied. These films were analysed using X‐ray diffraction, scanning electron microscopy, profilometry, optical transmittance, optical fluorescence, and second (SHG) and third harmonic generation (THG) techniques. A polycrystalline structure with a preferential growth along the ZnO(002) plane was found in all cases, with a corresponding average crystal size of less than 32 nm for the films. The morphology of the surfaces and some optical properties were found to be dependent on T S . The films deposited at low T S (400 °C) showed a uniform surface covered with needle‐like grains as well as SHG and THG response. In contrast, for the films deposited at 525 °C, a porous surface with irregular‐shaped grains was obtained and a substantial reduction of the SHG and THG response was detected. NLO χ (2) eff coefficients one order of magnitude larger than the χ (2) 11 component of an α‐quartz reference crystal were measured for all ZnO:F thin films. The χ (3) values of the samples, under resonant conditions, were in the interesting range of 10 –12 esu. Finally, a typical optical transmittance higher than 85% and a band gap ( E g ) of 3.4 eV were evaluated for films deposited under optimal conditions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)