Heteroepitaxial Na0.5K0.5NbO3/La0.5Sr0.5CoO3 electro-optical cell
2006 (English)In: Integrated Ferroelectrics, ISSN 1058-4587, Vol. 80, 133-143 p.Article in journal (Refereed) Published
We report electro-optic performance of heteroepitaxial Na0.5K0.5NbO3(1.5 mu m)/La0.5Sr0.5CoO3 (0.5 mu m) (NKN/LSCO) films grown on Al2O3(01 (1) under bar2) single crystal (r-cut sapphire) by rf-magnetron sputtering (NKN) and pulsed laser deposition (LSCO) techniques. Vertical capacitive electro-optical cells were defined by a thermal evaporation of 2 x 8 mm(2) Au electrodes through the contact mask on top the NKN film. Processing parameters have been specially optimized to obtain electrosoftNKN films with a non-linear fatigue-free P-E characteristics: low remnant P-r = 7.7 mu C/cm(2) high induced polarization P = 23 mu C/cm(2) @ 400 km/cm , and the coercive field E-c = 70 kV/cm. Electro-optical characterization of NKN films has been performed using waveguide refractometry: a prism coupling of a light beam into the thin-film waveguide modes. Intensity of TM- and TE-polarized light of 655 nm laser diode reflected from the free surface of NKN film and Au-clad NKN/LSCO waveguide was recorded at zero and 15 V (100 kV/cm) bias electric field. Fitting reflectivity spectra to Fresnel formulas yields extraordinary and ordinary refractive indices n(c) = 2.232 and n(o) = 2.234 as well as electro-optic coefficient r(13) = 17.4 pm/V. Dispersion of the refraction index follows Sellmeier formula n(2) = 1+ 3.46/[1 + (244 nm/lambda)(2)] in the range from 400 nm to 850 nm.
Place, publisher, year, edition, pages
2006. Vol. 80, 133-143 p.
sodium potassium niobate, ferroelectric films, pulsed laser deposition, rf-magnetron sputtering, electro-optic effect, prism coupling, waveguiding, refraction index, electro-optic coefficient, na0.5k0.5nbo3 thin-films, pulsed-laser deposition, knbo3, sapphire
Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-15801DOI: 10.1080/10584580600656684ISI: 000238680700016ScopusID: 2-s2.0-33745752523OAI: oai:DiVA.org:kth-15801DiVA: diva2:333843
QC 20100525 QC 20111003. Conference: 17th International Symposium on Integrated Ferroelectrics. Shanghai, PEOPLES R CHINA. APR 17-20, 2005.2010-08-052010-08-052011-10-03Bibliographically approved