Page 344 - Organic Electronics in Sensors and Biotechnology

Organic Electronics in Memories and Sensing Applications 321

Light (top)

x
S D

Au Au
t
d
C 60 + ZnPc

Interface BCB
x = 0
ITO

G

Light (bottom)

10 –5
10 –6
–5
10 2.2 mW; through ITO
10 –7 2.9 mW; through ITO
3.7 mW; through ITO
3.7 mW; through Au
I d (A) 10 –8 Drain current (A) 10 –6 2.9 mW; through Au
2.2 mW; through
Au
2.9 mW; 780 nm
10 –9 λ = 780 nm 2.2 mW; 780 nm
–60 –30 0 30 60 3.7 mW; 780 nm
Gate voltage (V) Dark
10 –10 21 μW; 530 nm
66 μW; 530 nm
110 μW; 530 nm
10 –11
–60 –40 –20 0 20 40 60
V g (V)
FIGURE 8.17 Top: Device scheme of the C and ZnPc-based
60
phototransistors. Bottom: Photoresponse of the above device fabricated
in the author’s laboratory. (See also color insert.)

far very little is known about the origin of the nature of charge trans-
90
port under illumination and whether it is unipolar or ambipolar.
Ambipolar transport is sensitive to the interface between the organic
semiconductor and the gate dielectric as well as the nature of the
23