TITLE:
Temperature Dependence of Electrical Properties of Organic Thin Film Transistors Based on pn Heterojuction and Their Applications in Temperature Sensors
AUTHORS:
Rongbin Ye, Koji Ohta, Mamoru Baba
KEYWORDS:
Organic Thin Film Transistors, pn Heterojunction, Temperature Dependence, Temperature Sensors
JOURNAL NAME:
Journal of Computer and Communications,
Vol.4 No.5,
May
26,
2016
ABSTRACT: Organic thin film
transistors based on an F16CuPc/α6T
pn heterojunction have been fabricated and analyzed to investigate the
temperature dependence of electrical properties and apply in temperature
sensors. The mobility follows a thermally activated hopping process. At temperatures
over 200 K, the value of thermal activation energy (EA) is 40. 1 meV, similar to that of the single-layer
device. At temperatures ranging from 100 to 200 K, we have a second regime with
a much lower EA of 16.3
meV, where the charge transport is dominated by shallow traps. Similarly, at
temperatures above 200 K, threshold voltage (VT) increases linearly with decreasing temperature, and
the variations of VT of
0.185 V/K is larger than the variation of VT (~0.020 V/K) in the single layer devices. This result is due to the interface dipolar
charges. At temperatures ranging from 100 K to 200 K, we have a second regime
with much lower variations of 0.090 V/K. By studying gate voltage (VG)-dependence temperature
variation factor (k), the maximum value of k (~0.11 dec/K) could be obtained at VG = 5 V. Furthermore, the pn
heterojunction device could be characterized as a temperature sensor well
working at low operating voltages.