The determination method of the membrane thickness of ITO (InSnO2). The magnetite nanoparticles in the electric field migrate, forming the thin layer near conductive ITO membrane with varying thickness. Lighting this structure by monochromatic plane polarized light the interference of light in the thin membrane was observed. The experimental values of the intensity of the reflected light from the surface of «ITO – layer of magnetite particles" for samples with different thickness of the conductive coating

Chekanov, V.S.

Chekanov, V.V.

Kandaurova, N.V.

Journal of Nano- and Electronic Physics

SocioEconomic Challenges Journal (Sumy State University)

JOURNAL OF NANO- AND ELECTRONIC PHYSICS ЖУРНАЛ НАНО- ТА ЕЛЕКТРОННОЇ ФІЗИКИ 
Vol. 8 No 4(1), 04045(3pp) (2016) Том 8 № 4(1), 04045(3cc) (2016) 
 
 
2077-6772/2016/8(4(1))04045(3) 04045-1  2016 Sumy State University 
Short Communication 
 
Thickness Calculation of Thin Transparent Conductive Membrane on the Border with a 
Magnetic Fluid 
 
V.V. Chekanov, N.V. Kandaurova*, V.S. Chekanov† 
 
North Caucasus Federal University 2, Kulakova prosp., 355029 Stavropol, Russia 
 
(Received 08 October 2016; published online 29 November 2016) 
 
The determination method of the membrane thickness of ITO (InSnO2). The magnetite nanoparticles in 
the electric field migrate, forming the thin layer near conductive ITO membrane with varying thickness. 
Lighting this structure by monochromatic plane polarized light the interference of light in the thin mem-
brane was observed. The experimental values of the intensity of the reflected light from the surface of «ITO 
– layer of magnetite particles" for samples with different thickness of the conductive coating.  
 
Keywords: Thin membrane, Interference, Electric field, Magnetic fluid. 
 
DOI: 10.21272/jnep.8(4(1)).04045 PACS numbers: 75.50.Mm, 79.60.Jv 
 
 
                                                             
* candaur18@yandex.ru 
† oranjejam@mail.ru 
1. INTRODUCTION 
 
In [1] the membrane thickness of magnetite nano-
particles on the surface of the transparent conductive 
electrode in the electric field was calculated. 
The purpose of this study – the calculation of the 
thickness of the conductive ITO coating and investigate 
the dynamics of the formation of the near-electrode 
layer (two-layer thin membrane) optical methods, in-
cluding a description of a new phenomenon – the elec-
trically interference from thin transparent two-layer 
membrane, one layer of which – conductive coating 
(ITO), and the second layer – magnetite particles. Prac-
tically, this phenomenon may be applied to determine 
the thickness ITO- membranes used as a transparent 
electric-coating layers for displays, solar cells, etc. if it 
is impossible to measure the thickness of traditional 
(such as inaccessibility), the measurement of the thick-
ness of electrochromic glass coatings for aircraft win-
dows, the design of multi-use sensors [2, 3], that de-
termines the relevance of this work 
 
2. THE EXPERIMENTAL DEVICE AND TECH-
NIQUE OF THE EXPERIMENT 
 
Apparatus for observing the reflected light intensity 
change in the electric field is a parallel cell (Figure 1) 
Consisting of two electrodes, one of which – the glass 
coated with transparent conductive (ITO). In order to 
eliminate glare from the surface of the cell a glass prism 
is installed on it. Between the electrodes is a colloidal 
solution - magnetic fluid type "magnetite in kerosene." 
Magnetite concentration - 3.2% vol. The dielectric con-
stant ε  2,7, conductivity 75 10   (Ω·m – 1) (measured 
at a frequency of 100 Hz). The average size of the mag-
netite particles ~ 10 nm, the thickness of the protective 
envelope consisting of molecules HOl ~ 1,5 nm. 
In the face of the prism, glued to the glass by immer-
sion liquid (Figbre 1) falls a beam diameter of 2 mm from 
the laser pointer (  650 nm) so that the angle θ of fall-
ing on the glass surface is 45 degrees. The beam is re-
flected from the surface of the "glass-conductive coating" 
and "conductive coating - magnetic fluid" and inter-
feres. Reflected beam falls through the diaphragm – 6, 
and polaroid – 7 on a photodiode FD-256. The photodi-
ode is connected to the input of a two-beam oscilloscope 
GDS-71022, which allows us to observe the dependence 
of the voltage on the photodiode from time on the 
screen and memorize the results in tabular form (4000 
points). The rays reflected from the boundaries of the 
"prism-glass" and the layer "conductive coating – mag-
netic fluid" spatially separated ~ 5 mm. In order to 
avoid glare of a photodiodes a diaphragm with orifice 
about 1 mm was placed in front polaroid 7. Laser and 
polaroid can be rotated over the beam. The plane of polar-
ization of the polaroid 10 coincides with the plane of polar-
ization of the laser beam. Polaroid serve to reduce the 
depolarized component of the laser light. Rotating the 
laser with a polaroid we try to achieve the s-component 
(TE-wave) to be perpendicular to the plane of falling. Ro-
tating the polaroid 7 we weakened the light so that photo-
diode operated in the linear mode. The area of the elec-
trode surface S  36  30 mm2, thickness of the magnetic 
layer of liquid l – 250 mcm. In the experiments we used  
two samples of coated glass (manufactured by LLC «Poly-
tech», St.-Petersburg). Glass thickness for two samples –  
 
 
 
Fig. 1 – Schematic of the experimental device to observe the 
 V.V. CHEKANOV, N.V. KANDAUROVA, V.S. CHEKANOV J. NANO- ELECTRON. PHYS. 8, 04045 (2016) 
 
 
04045-2 
changes in the reflected light intensity. 1 – magnetic fluid; 2 – 
plate of Micarta foil; 3,11 – isolation pads made of polystyrene; 
4 – a transparent conductive coated glass (ITO); 5 – isosceles 
rectangular prism; 6 – diaphragm; 7, 10 – Polaroids; 8 – a 
photodiode; 9 – Laser Pointer; 12 – electrodes 
4 mm, thickness of the conducting coating sample No 1 
h01  (280 ± 5) nm, sample No 2 h02  (215 ± 5) nm. 
Measurements were made at five different points on 
the surface, and then averaged. 
Fig. 2 a, b are graphs showing the change in voltage 
in the photodiode (optical response) with time depend-
ence for two samples of glass, c – view of voltage ap-
plied to the cell electrodes. 
The shape of curves is explained as follows: at the 
beginning of the period of zero voltage (points A1 and A2 
in Figures 2a, b) the optical response is fixed. Then, 
with increasing voltage, the reflectance changes (A1B1 
and A2B2 plots on the curves of Figures 2a, b). Optical 
signal responses have distinct peak (Figure 2a) and 
minimum (Figure 2b), which is characteristic of inter-
ference in thin membranes. At a certain critical voltage  
(~ 12 V) the intensity of the reflected light begins to 
change periodically (B1C1 areas and B2C2), indicating a 
periodic variation (fluctuation) of the layer thickness. 
 
 
 
Fig. 2 – The time dependence of the intensity of reflected light 
from the surface "conductive coating – a layer of densely 
packed particles of magnetite" (clarifications in the text) 
 
In the absence of an electric field magnetic liquid in 
a cell is homogeneous, however, when the field exists – 
solid phase particles under the influence of electro-
dypolophoresis and begin to migrate to the electrodes 
at the electrode surface and the conductive coating con-
centration of magnetite particles apparently increases 
to a maximum value (25-27 vol.%) in which it has not 
lost fluidity. This concentration corresponds to the 
dense packing of spheres with a diameter ~ 12 nm.  
Complex refractive index and thickness of the con-
ductive coating were measured with a spectroscopic 
ellipsometer SE 800 SENTECH. Refractive index of 
glass 1n   1,52, the refractive index of the conductive 
coating 2nˆ   1,76 (1 + 0,04 i). The refractive indexes of 
the magnetic fluid concentration 3,2 vol.% –
3nˆ  = 1,45 (1 + 0,01 i), concentration 26 vol.% –
 4nˆ = 1,75 (1 + 0,03i). Note that 2nˆ  ≈ 4nˆ , ie the growth 
of concentrated magnetic fluid layer by the optical 
properties is equivalent to an increase in the thickness 
of the conductive coating of ITO. Thus R – reflectance 
of the conductive coating with a layer of densely packed 
particles of magnetite, is a function of [4]: 
 
 ),,ˆ,ˆ,,( 321 nnnhRR  , (1) 
 
where h  h0 + Δh, θ  45°– angle of light falling on the 
glass,   650 nm – wavelength, Δh – the thickness of 
the sheath , h0 – thickness of the conductive coating. 
Due to cumbersome formulas given only the result 
of the calculation of R(h), as shown in Fig. 3. 
 
 
 
Fig. 3 – The dependence of the reflection coefficient R of a thin 
membrane of thickness h 
 
Using the experimental results shown in Figure 2 
and calculated dependence of R(h), as shown in Fig-
ure 3, the method of determining the thickness of the 
conductive coating which varies depending on the ap-
plied electric field and the thickness of ITO sheath has 
been developed. 
In the calculation of the curve R(h) points A1 and A2 
corresponds to the thickness of the conductive coating 
samples No 1 and No 2 – h01 and h02 and the values of 
reflection coefficients R01  0,01 and R02  0,026. 
Given that the photodiode operates in the linear 
mode, the voltage at the input resistor of the oscillo-
scope U is proportional to the intensity of the reflected 
light and to the reflectance R. That is, knowing the 
dependence U1(t) and U2(t) reflection coefficients can be 
found for the samples No 1 and No 2 using the experi-
mental data (Figure 2). The points B1 and B2 (Figure 2) 
corresponds to the beginning of periodic variation (os-
cillation) of the layer thickness, consisting of packed 
particles of magnetite, which is formed in the electric 
field at the surface of the conductive coating. Finding 
 THICKNESS CALCULATION OF THIN TRANSPARENT CONDUCTIVE MEMBRANE… J. NANO- ELECTRON. PHYS. 8, 04045 (2016) 
 
 
04045-3 
the values of the reflection coefficients which are rele-
vant to B1 and B2 experimental points (Figure 2), we 
find the point B1 and B2 on the calculated dependence 
(Figure 3). The abscissas of the points B1 and B2 are the 
required thickness values h1 and h2. Found by this 
method the thickness of the sample No 1 and No 2: 
h1  (365 ± 5) nm, h2  (301 ± 5) nm, value Δh the 
thickness of the near-electrode layer of magnetite par-
ticles – Δh1  Δh2  (98 ± 5) nm and, respectively, ITO-
coating thickness h01  (280 ± 5) nm and 
h02  (215 ± 5) nm. In view of the previously measured 
ellipsometer SE 800 SENTECH thickness values for 
conductive coatings and samples No 1 and No 2 ap-
peared that the difference in results of these independ-
ent measurements of at least 10 %. 
 
3. СONCLUSIONS 
 
In this article has been developed a method of calcu-
lating the conductive thin membrane thickness, con-
sisting of a located on glass transparent coating ITO,  
which is one of the electrodes in the electrochemical cell 
with a magnetic fluid. The optical properties of the 
structure «ITO nanoparticles of magnetite – layer 
membrane» in the electric field were discovered. It is 
found that by adjusting the voltage on the electrodes, it 
is possible to change the thickness of the layer of mag-
netite nanoparticles. By comparing the intensity of the 
reflected light from the time the results of mathemati-
cal modeling, it was possible to determine the thickness 
of the double-layered structure «ITO-magnetite» and 
magnetite nanoparticles sheath thickness, consequent-
ly, the thickness of the two samples conductive ITO 
membrane. Comparison with conductive coating thick-
ness measurements for these samples using the spec-
troscopic ellipsometer 800 SE SENTECH showed that 
within the errors of the same to within 10 %. 
 
 
REFERENCES 
 
1. V.V. Chekanov, N.V. Kandaurova V.S. Chekanov, J. Nano-
 Electron. Phys 7 No 4, 04041 (2015). 
2. V.V. Chekanov, N.V. Kandaurova, Y.A. Rakhmanina 
V.S. Chekanov, Pat. 2449382, Russian Federation, IPC 
G09F 9/30 G02F 1/167, publ. 27.04.2012. Bull. №12. - 5. : 
Ill. 
3. V.V. Chekanov, N.V. Kandaurova, Y.A. Rakhmanina 
V.S. Chekanov, Pat. 2446422, Russian Federation, IPC 
G02F1 1/167, publ. 27.03.2012. Bull. №9. - 4. : Ill. 
4. M. Born, E. Volf, Principles of Optics (M.: Nauka: 1973). 
 


Thickness Calculation of Thin Transparent Conductive Membrane on the Border with a Magnetic Fluid

Electronic Sumy State University Institutional Repository

JOURNAL OF NANO- AND ELECTRONIC PHYSICS ЖУРНАЛ НАНО- ТА ЕЛЕКТРОННОЇ ФІЗИКИ Vol. 8 No 4(1), 04045(3pp) (2016) Том 8 № 4(1), 04045(3cc) (2016)   2077-6772/2016/8(4(1))04045(3) 04045-1  2016 Sumy State University Short Communication  Thickness Calculation of Thin Transparent Conductive Membrane on the Border with a Magnetic Fluid  V.V. Chekanov, N.V. Kandaurova*, V.S. Chekanov†  North Caucasus Federal University 2, Kulakova prosp., 355029 Stavropol, Russia  (Received 08 October 2016; published online 29 November 2016)  The determination method of the membrane thickness of ITO (InSnO2). The magnetite nanoparticles in the electric field migrate, forming the thin layer near conductive ITO membrane with varying thickness. Lighting this structure by monochromatic plane polarized light the interference of light in the thin mem-brane was observed. The experimental values of the intensity of the reflected light from the surface of «ITO – layer of magnetite particles" for samples with different thickness of the conductive coating.   Keywords: Thin membrane, Interference, Electric field, Magnetic fluid.  DOI: 10.21272/jnep.8(4(1)).04045 PACS numbers: 75.50.Mm, 79.60.Jv                                                                * candaur18@yandex.ru † oranjejam@mail.ru 1. INTRODUCTION  In [1] the membrane thickness of magnetite nano-particles on the surface of the transparent conductive electrode in the electric field was calculated. The purpose of this study – the calculation of the thickness of the conductive ITO coating and investigate the dynamics of the formation of the near-electrode layer (two-layer thin membrane) optical methods, in-cluding a description of a new phenomenon – the elec-trically interference from thin transparent two-layer membrane, one layer of which – conductive coating (ITO), and the second layer – magnetite particles. Prac-tically, this phenomenon may be applied to determine the thickness ITO- membranes used as a transparent electric-coating layers for displays, solar cells, etc. if it is impossible to measure the thickness of traditional (such as inaccessibility), the measurement of the thick-ness of electrochromic glass coatings for aircraft win-dows, the design of multi-use sensors [2, 3], that de-termines the relevance of this work  2. THE EXPERIMENTAL DEVICE AND TECH-NIQUE OF THE EXPERIMENT  Apparatus for observing the reflected light intensity change in the electric field is a parallel cell (Figure 1) Consisting of two electrodes, one of which – the glass coated with transparent conductive (ITO). In order to eliminate glare from the surface of the cell a glass prism is installed on it. Between the electrodes is a colloidal solution - magnetic fluid type "magnetite in kerosene." Magnetite concentration - 3.2% vol. The dielectric con-stant ε  2,7, conductivity 75 10   (Ω·m – 1) (measured at a frequency of 100 Hz). The average size of the mag-netite particles ~ 10 nm, the thickness of the protective envelope consisting of molecules HOl ~ 1,5 nm. In the face of the prism, glued to the glass by immer-sion liquid (Figbre 1) falls a beam diameter of 2 mm from the laser pointer (  650 nm) so that the angle θ of fall-ing on the glass surface is 45 degrees. The beam is re-flected from the surface of the "glass-conductive coating" and "conductive coating - magnetic fluid" and inter-feres. Reflected beam falls through the diaphragm – 6, and polaroid – 7 on a photodiode FD-256. The photodi-ode is connected to the input of a two-beam oscilloscope GDS-71022, which allows us to observe the dependence of the voltage on the photodiode from time on the screen and memorize the results in tabular form (4000 points). The rays reflected from the boundaries of the "prism-glass" and the layer "conductive coating – mag-netic fluid" spatially separated ~ 5 mm. In order to avoid glare of a photodiodes a diaphragm with orifice about 1 mm was placed in front polaroid 7. Laser and polaroid can be rotated over the beam. The plane of polar-ization of the polaroid 10 coincides with the plane of polar-ization of the laser beam. Polaroid serve to reduce the depolarized component of the laser light. Rotating the laser with a polaroid we try to achieve the s-component (TE-wave) to be perpendicular to the plane of falling. Ro-tating the polaroid 7 we weakened the light so that photo-diode operated in the linear mode. The area of the elec-trode surface S  36  30 mm2, thickness of the magnetic layer of liquid l – 250 mcm. In the experiments we used  two samples of coated glass (manufactured by LLC «Poly-tech», St.-Petersburg). Glass thickness for two samples –     Fig. 1 – Schematic of the experimental device to observe the  V.V. CHEKANOV, N.V. KANDAUROVA, V.S. CHEKANOV J. NANO- ELECTRON. PHYS. 8, 04045 (2016)   04045-2 changes in the reflected light intensity. 1 – magnetic fluid; 2 – plate of Micarta foil; 3,11 – isolation pads made of polystyrene; 4 – a transparent conductive coated glass (ITO); 5 – isosceles rectangular prism; 6 – diaphragm; 7, 10 – Polaroids; 8 – a photodiode; 9 – Laser Pointer; 12 – electrodes 4 mm, thickness of the conducting coating sample No 1 h01  (280 ± 5) nm, sample No 2 h02  (215 ± 5) nm. Measurements were made at five different points on the surface, and then averaged. Fig. 2 a, b are graphs showing the change in voltage in the photodiode (optical response) with time depend-ence for two samples of glass, c – view of voltage ap-plied to the cell electrodes. The shape of curves is explained as follows: at the beginning of the period of zero voltage (points A1 and A2 in Figures 2a, b) the optical response is fixed. Then, with increasing voltage, the reflectance changes (A1B1 and A2B2 plots on the curves of Figures 2a, b). Optical signal responses have distinct peak (Figure 2a) and minimum (Figure 2b), which is characteristic of inter-ference in thin membranes. At a certain critical voltage  (~ 12 V) the intensity of the reflected light begins to change periodically (B1C1 areas and B2C2), indicating a periodic variation (fluctuation) of the layer thickness.    Fig. 2 – The time dependence of the intensity of reflected light from the surface "conductive coating – a layer of densely packed particles of magnetite" (clarifications in the text)  In the absence of an electric field magnetic liquid in a cell is homogeneous, however, when the field exists – solid phase particles under the influence of electro-dypolophoresis and begin to migrate to the electrodes at the electrode surface and the conductive coating con-centration of magnetite particles apparently increases to a maximum value (25-27 vol.%) in which it has not lost fluidity. This concentration corresponds to the dense packing of spheres with a diameter ~ 12 nm.  Complex refractive index and thickness of the con-ductive coating were measured with a spectroscopic ellipsometer SE 800 SENTECH. Refractive index of glass 1n   1,52, the refractive index of the conductive coating 2nˆ   1,76 (1 + 0,04 i). The refractive indexes of the magnetic fluid concentration 3,2 vol.% –3nˆ  = 1,45 (1 + 0,01 i), concentration 26 vol.% – 4nˆ = 1,75 (1 + 0,03i). Note that 2nˆ  ≈ 4nˆ , ie the growth of concentrated magnetic fluid layer by the optical properties is equivalent to an increase in the thickness of the conductive coating of ITO. Thus R – reflectance of the conductive coating with a layer of densely packed particles of magnetite, is a function of [4]:   ),,ˆ,ˆ,,( 321 nnnhRR  , (1)  where h  h0 + Δh, θ  45°– angle of light falling on the glass,   650 nm – wavelength, Δh – the thickness of the sheath , h0 – thickness of the conductive coating. Due to cumbersome formulas given only the result of the calculation of R(h), as shown in Fig. 3.    Fig. 3 – The dependence of the reflection coefficient R of a thin membrane of thickness h  Using the experimental results shown in Figure 2 and calculated dependence of R(h), as shown in Fig-ure 3, the method of determining the thickness of the conductive coating which varies depending on the ap-plied electric field and the thickness of ITO sheath has been developed. In the calculation of the curve R(h) points A1 and A2 corresponds to the thickness of the conductive coating samples No 1 and No 2 – h01 and h02 and the values of reflection coefficients R01  0,01 and R02  0,026. Given that the photodiode operates in the linear mode, the voltage at the input resistor of the oscillo-scope U is proportional to the intensity of the reflected light and to the reflectance R. That is, knowing the dependence U1(t) and U2(t) reflection coefficients can be found for the samples No 1 and No 2 using the experi-mental data (Figure 2). The points B1 and B2 (Figure 2) corresponds to the beginning of periodic variation (os-cillation) of the layer thickness, consisting of packed particles of magnetite, which is formed in the electric field at the surface of the conductive coating. Finding  THICKNESS CALCULATION OF THIN TRANSPARENT CONDUCTIVE MEMBRANE… J. NANO- ELECTRON. PHYS. 8, 04045 (2016)   04045-3 the values of the reflection coefficients which are rele-vant to B1 and B2 experimental points (Figure 2), we find the point B1 and B2 on the calculated dependence (Figure 3). The abscissas of the points B1 and B2 are the required thickness values h1 and h2. Found by this method the thickness of the sample No 1 and No 2: h1  (365 ± 5) nm, h2  (301 ± 5) nm, value Δh the thickness of the near-electrode layer of magnetite par-ticles – Δh1  Δh2  (98 ± 5) nm and, respectively, ITO-coating thickness h01  (280 ± 5) nm and h02  (215 ± 5) nm. In view of the previously measured ellipsometer SE 800 SENTECH thickness values for conductive coatings and samples No 1 and No 2 ap-peared that the difference in results of these independ-ent measurements of at least 10 %.  3. СONCLUSIONS  In this article has been developed a method of calcu-lating the conductive thin membrane thickness, con-sisting of a located on glass transparent coating ITO,  which is one of the electrodes in the electrochemical cell with a magnetic fluid. The optical properties of the structure «ITO nanoparticles of magnetite – layer membrane» in the electric field were discovered. It is found that by adjusting the voltage on the electrodes, it is possible to change the thickness of the layer of mag-netite nanoparticles. By comparing the intensity of the reflected light from the time the results of mathemati-cal modeling, it was possible to determine the thickness of the double-layered structure «ITO-magnetite» and magnetite nanoparticles sheath thickness, consequent-ly, the thickness of the two samples conductive ITO membrane. Comparison with conductive coating thick-ness measurements for these samples using the spec-troscopic ellipsometer 800 SE SENTECH showed that within the errors of the same to within 10 %.   REFERENCES  1. V.V. Chekanov, N.V. Kandaurova V.S. Chekanov, J. Nano- Electron. Phys 7 No 4, 04041 (2015). 2. V.V. Chekanov, N.V. Kandaurova, Y.A. Rakhmanina V.S. Chekanov, Pat. 2449382, Russian Federation, IPC G09F 9/30 G02F 1/167, publ. 27.04.2012. Bull. №12. - 5. : Ill. 3. V.V. Chekanov, N.V. Kandaurova, Y.A. Rakhmanina V.S. Chekanov, Pat. 2446422, Russian Federation, IPC G02F1 1/167, publ. 27.03.2012. Bull. №9. - 4. : Ill. 4. M. Born, E. Volf, Principles of Optics (M.: Nauka: 1973).  

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Thickness Calculation of Thin Transparent Conductive Membrane on the Border with a Magnetic Fluid

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