Page 172 - Organic Electronics in Sensors and Biotechnology

Integrated Pyr oelectric Sensors 149

Temperature lift Current response
10 nm 10 nm
150 nm 10 –7 150 nm
10 2 400 nm 400 nm
1 μm 1 μm
Temperature lift (K) 10 –2 100 μm Current (A) 10 –8 100 μm
10 μm
10 μm
10 0
10 –9
10 –4
10 –4 10 –2 10 0 10 2 10 4 10 6 10 –4 10 –2 10 0 10 2 10 4 10 6
Frequency (Hz) Frequency (Hz)
(a)
Temperature lift Current response
10 4
10 nm 10 nm
150 nm 10 –6 150 nm
10 2 400 nm 400 nm
1 μm
Temperature lift (K) 10 –2 10 μm Current (A) 10 –7 10 μm
1 μm
10 0
100 μm
100 μm
10 –4 10 –8
10 –6 10 –9
10 –4 10 –2 10 0 10 2 10 4 10 6 10 –4 10 –2 10 0 10 2 10 4 10 6
Frequency (Hz) Frequency (Hz)
(b)
Temperature lift Current response
10 4
10 nm 10 nm
150 nm 150 nm
10 2 400 nm 400 nm
1 μm 10 –7 1 μm
Temperature lift (K) 10 –2 100 μm Current (A) 10 –8 100 μm
10 μm
10 μm
10 0
10 –4
10 –9
10 –4 10 –2 10 0 10 2 10 4 10 6 10 –4 10 –2 10 0 10 2 10 4 10 6
Frequency (Hz) Frequency (Hz)
(c)
FIGURE 4.19 Temperature lift and current response with different
thicknesses of the pyroelectric layer on 200 μm thick substrate of (a) glass,
(b) silicon, and (c) PET, calculated for the values of R = 100 MΩ and C = 75 pF.
i i
(See also color insert.)
basically frequency-independent below 1 Hz, and this level increases
with the resistance (Fig. 4.20).

Two-Dimensional Model
The one-dimensional model gives a relatively good picture of the ther-
mal penetration of the device and is, by the use of an appropriate
equivalent circuit, able to explain the measured pyroelectric responses
very well. However, since it is a one-dimensional model, no information
on the lateral resolution can be obtained from this approach. A two-
dimensional model of the heat transfer in the sensor element was there-
fore developed to give further insight in the lateral thermal distribution.