Influence of Temperature and Pentacene Thickness on the Electrical Parameters in Top Gate Organic Thin Film Transistor

Abstract

In this contribution, we report on the effect of pentacene thickness and temperature on the performance of top gate transistors. We first investigated the temperature dependence of the transport properties in the temperature range of 258 K -353 K. The electrical characteristics showed that the threshold voltage (V T ) and the onset voltage (V on ) remain unchanged. However, the subthreshold current (I off ), the on-current (I on ) and the field effect mobility (µ) are highly affected with a slight deterioration of subthreshold slope. We observed Arrhenius-like behavior suggesting a thermally activated mobility with an activation energy E A = 68 meV. Moreover the dependence of the charge carrier mobility on the organic semiconductor thickness has also been studied. The mobility decreased as the pentacene thickness increases whereas the threshold voltage and I off current remain minimally affected. In order to understand the transport properties and in view to put in light morphology peculiarities of pentacene, AFM images were performed. It turns out that the pentacene grain sizes are smaller and disorganized as the film thickness increases, and charge carriers are more prone to be trapped, leading to decrease the field effect mobility and the I on current. The devices were also tested under bias stress and the transistors with low thicknesses exhibited a relatively good electrical stability compared to those with high pentacene thicknesses. This work points out the influence of temperature, semiconductor thickness and bias stress effect on the device performance and stability of transistor using top gate configuration.

Scaling of top-gate/bottom-contact pentacene-based organic field-effect transistors with amorphous rubrene gate insulator

“…8. 7,[22][23][24][25][26][27][28][29][30][31][32][33][34][35] Although the mobility is not high enough, the lowest operation voltage of −5 V was realized in this research for the TG/BC OFET fabricated by the lift-off processes utilizing α-rubrene gate insulator.…”

Further Increasing the Accuracy of Characterization of a Thin Dielectric or Semiconductor Film on a Substrate from Its Interference Transmittance Spectrum

“…Optical dielectric and semiconductor thin films have numerous applications in research and development, in applied sciences and engineering [ 1 , 2 , 3 ]. For example, such films, with thicknesses of at least 300 nm, are used in solar cells [ 4 , 5 ], thin-film transistors [ 6 , 7 ], photonic circuits [ 8 , 9 ], holography [ 10 , 11 ], and thin-film batteries [ 12 , 13 ]. Since the optical properties of these kinds of films depend on their composition and technology of preparation, there is a quest for increasing the accuracy of the optical characterization of the films [ 14 , 15 ].…”

Selectablity of mechanical and dielectric properties of Parylene-C columnar microfibrous thin films by varying deposition angle

“…Furthermore, Parylene-C thin films show superior electrical insulation characteristics not only as passivation layers but also as gate dielectrics [15,17]. Therefore, ParyleneC has been explored for gate-dielectric application in different devices such as organic field-effect transistors [18], organic thin-film transistors [19], resistive randomaccess memories [20], biomedical sensors [21], and microelectromechanical systems [22].…”