Supplementary Information
Optoelectric Patterning: effect of electrode material and thickness on laser-induced AC
electrothermal flow
A. Mishra,a J.-W. Khora , K. Claytona, S. J. Williamsb, X. Panc, T. Kinzer-Ursemd and S. Wereleya
a
Birck Nanotechnology Center, School of Mechanical Engineering, Purdue University, West
Lafayette, IN, USA 47907.
b
Department of Mechanical Engineering, University of Louisville, KY, USA.
c
School of Mechatronics Engineering, Harbin Institute of Technology, China.
d
Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA 47907.
Figure S1: Experimental and simulated velocity profile produced by an 80 nm Ni layer with a
39.6 mW laser beam and 8 Vpp AC signal. The velocity profile was measured at a height of 190
µm from the bottom electrode.
Figure S2: Effect of laser power on velocity magnitude at different positions along z axis. Solid
lines are the linear fits to the corresponding data points. Velocity magnitude of the electrothermal
flow linearly increases as laser power is increased. For simulating the electrothermal flow, 25 nm
Ti films were selected as electrodes and an AC signal of 8 Vpp was selected.
Figure S3: Electrothermal velocity profile produced by laser induced heating of the 700 nm
ITO film at different positions along z axis. Laser power was kept at 1 mW, and an AC signal of
8 Vpp was applied between electrodes.
Figure S4: Electrothermal velocity profile produced by laser induced heating of the 12 nm
Ni film at different positions along z axis. Laser power was kept at 1 mW, and an AC signal of
8 Vpp was applied between electrodes.
Figure S5: Electrothermal velocity profile produced by laser induced heating of the 25 nm
Ti film at different positions along z axis. Laser power was kept at 1 mW, and an AC signal of
8 Vpp was applied between electrodes.
Table 1: Optical and thermal parameters of materials
Thermal
Absorption
Reflectance
Reflectance
Conductivity
Coefficient
(electrode-
(electrode-
(W/m/K)
(m-1)
air)
water)
0.09348
0.03369
0.08124
0.02638
0.1335
0.05696
0.39
-
0.2196
-
0.4384
0.3378
Thickness
Material
(nm)
ITO
70
3.21
ITO
350
5.9
ITO
700
10.22
Au
6.4
61.93
Ni
5.0
30.04
Ni
12.0
50.24
1.181×105
8.226×107
6.900×107
Ni
20.0
59.54
0.5863
-
Ni
50.0
72.04
0.7617
-
Ti
25.0
11.62,5
4.734×107
0.4877
0.3851
Pt
15.0
206
7.042×107
0.5227
-
Table 2: Properties of the solution
Property
Value
Relative Permittivity
80
Electrical Conductivity (mS/m)
8.8
Thermal Conductivity (W/m·K)
0.59
Density (kg/m3)
999.65
Dynamic Viscosity (N·s/m2)
0.001
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