- 1. UTB 2012 Vladimr Bobusk, Jan Mrzek, Ondej Podrazk Institute
of Photonics and Electronics ASCR v.v.i, Chabersk 57, 182 51
Prague, Czech Republic Special optical fibers and fiber capillaries
coated with Indium-Tin-Oxide
2. Outline Introduction Definition, motivation Preparation of
ITO (Indium-Tin-Oxide) films Planar substrates, Fiber optics
Characterization Electrical properties, Optical Properties
Conclusions SPIE 2013 3. Goals UTB 2012 SPIE 2013 Preparation of
ITO thin films from colloidal solution by dip- coating method
Characterization of electrical and optical properties and
comparison to other methods 4. Widely used transparent
semiconductor Electrically conductive Optically transparent Huge
applications in markets: Introduction Indium-Tin-Oxide (ITO) SPIE
2013 OLEDTouch panelsFlat panel displays Solar Cells 5. Preparation
of ITO thin films Chemical depositionPhysical deposition Advantage
& Drawbacks Phys Chem Colloids Well tailored thickness
Application inside cavities Large deposition area Quick preparation
Magnetron sputtering Chemical approaches Deposition of colloids
SPIE 2013 6. Preparation SPIE 2013 ITO Colloidal solution Sigma
Aldrich Dispersion in isopropanol Dip-coating Thermal treatment 150
- 600C Characterization Electrical and Optical properties 7.
Deposition Proportionality of ITO film thickness and the
withdrawing speed SPIE 2013 0 50 100 150 200 200 250 300 350 400
450 500 550 Thickness(nm) Withdrawing speed (mmmin -1 ) The
withdrawing speed is the most flexible parameter 8. Electrical
properties Thermal treatment Monotonous decrease of resistivity
SPIE 2013 Chemical approach Achieved 0,11 *mm Achieved 5,70 *mm
Colloidal approach DC magnetron sputtering Achieved 0,04 *mm [1]
Thin Solid Films Papers 411(1) (2002) 42 - 45 [2] Thin Solid Films
270 (1995) 37- 42 1 2 9. SPIE 2013 Temporal variation of the
resistivity Investigation of factors responsible for the changing
resistivity Electrical properties Temporal stability 10. UTB 2012
SPIE 2013 Resistivity relative changes due to concentration of
water in atmosphere 4 6 8 10 12 14 16 18 100 200 300 400 500 600
Relativechangesoftheresistivity(%) Partial pressure of water (kPa)
Porosity of prepared ITO films Electrical properties Humidity
interferences 11. UTB 2012 SPIE 2013 High porosity showed by AFM
and SEM Morfology of prepared films Imprinted nanoparticles shape
AFM scan of ITO film SEM of ITO film 12. UTB 2012 SPIE 2013
Calculated Refractive index Value of the refractive index is lower
than the value 2,0 400 500 600 700 800 1.4575 1.4580 1.4585 1.4590
1.4595 1.4600 Refractiveindex Wavelength (nm) n( )=A+ B 2 + C 4
Optical properties Spectral ellipsometry Cauchys dispersion
relations 3,4 [3] Vacuum, paper 1191, (1994), 45 (12) [4] Japanese
Journal of Applied Physics, (2009), 48 n refractive index A, B, C,
- fitted constants -wavelength n = 1,457 for = 632 nm 13. Planar
substrate UTB 2012 SPIE 2013 Refractive index of layer n = 1,46
High porosity of ITO layer 54% pores in coated films Theory of
effective media: 14. Electrical properties Optical fibers UTB 2012
SPIE 2013 0 30 60 90 120 150 180 0 5 10 15 20 25 Resistance(M)
Length (mm) Preparation method of ITO films alike on planar
substrates The optical fiber with diameters lower than 250m and
inhomogenous ITO layers High resistance of ITO films coated on the
fibers 15. Optical properties Optical fibers UTB 2012 SPIE 2013 -30
-20 -10 0 10 20 30 0.0 0.2 0.4 0.6 0.8 1.0 ITO coating PCS fiber
Normalizedoutputpower Angle of incidence (deg) Angular distribution
of output power numerical aperture (NA) The calculated value of
numerical aperture for PCS fiber Refractive index of ITO cladding
NA=ncore 2 ncladding 2 NA = 0,1078 16. UTB 2012 SPIE 2013 Summary
High resistivity Planar substrate 0,11 *mm Optical fiber 150 M*mm
Colloidal solution ITO High adsorption properties Large surface
area High porosity 54% Refractive index n = 1,457 17. UTB 2012 SPIE
2013 General Conclusions Colloidal solution ITO ITO thin films
prepared on planar substrates and optical fibers by dip-coating
Easy and quick preparation of films with determined thickness
Strong dependence of the resistivity on the humidity Preparation
inside of capillaries and on the optical fibers Homogeneity of ITO
layers Suitable for sensors 18. UTB 2012 SPIE 2013 Thank you for
your attention Acknowledgement: The research was supported by the
Grant Agency of the Czech Republic, project No. 102/10/2139 I thank
to my collegues Petra Lebrukov and Zdek Jarchovsk for their help
with AFM and SEM analysis. 19. Characterization of ITO films UTB
2012 SPIE 2013 Multimeter TD2000 Profilometer Tercor Alfa
Ellipsometery Sentech 850SE spectral ellipsometer RTA AFM SEM Lyra
3 Tescan 20. UTB 2012 SPIE 2013 Contact: Vladimr Bobusk
[email protected] 732286880
