Contact effects in high performance fully printed p-channel organic thin film transistors

Abstract

Contact effects have been investigated in fully printed p-channel organic thin film transistors with field effect mobility up to 2 cm2/Vs. Electrical characteristics of the organic thin film transistors, with channel length <200lm, are seriously influenced by contact effects with an anomalous increase of the contact resistance for increasing source-drain voltage. Assuming that contact effects are negligible in long channel transistors and using gradual channel approximation, we evaluated the current-voltage characteristics of the injection contact, showing that I-V characteristics can be modeled as a reverse biased Schottky diode, including barrier lowering induced by the Schottky effect

Unified drain-current model of complementary p- and n-type OTFTs

“…This is evident from the output characteristics shown in Fig. 6 and, according to several studies [51,52,53,54], we verified that it is due to the parasitic contact resistance at the source injecting contact. This is further confirmed by the normalized transfer characteristics shown in Fig.…”

Temperature dependence of the current in Schottky-barrier source-gated transistors

“…Thus, at high electric field, the barrier in this region of the source can be modulated, and since the reverse current of the contact is exponentially dependent on effective barrier height 20 , large changes in current (I 1 ) can be effected by changing the potential on the gate. The drain bias, however, has a similar effect on this area of the source, so without purposeful screening of the source edge from drain electric field 11 , output characteristics have a drain voltage dependence of the current in saturation 5,9 .…”

“…Regardless of the current injection mechanism at the source 3,5,6 , the intentional use of a source barrier in an otherwise conventional TFT structure leads to major differences in the transistor (output) characteristic: low-voltage saturation 2,3,[7][8][9][10] , flat saturated output characteristics 3,7,9,11 , tolerance to geometrical variations 4,12 , bias stress stability 13 and improved current levels in low mobility materials 14 . Both digital 15 and analog applications 14,[16][17][18][19] could benefit from using these devices, in terms of amplification, energy efficiency, uniformity of electrical performance, and reliability.…”

“…In the y direction, the resistance is given by the average resistivity of the semiconductor and its thickness. (Figure 1d) 3,9 The reverse biased source barrier (D s in Figure 1d) plays a role in current control, not as a current-limiting mechanism, but rather as a non-linear potential drop. Simply, the second mechanism is a two-dimensional potential gradient problem, in which (for…”

Analogue Frontend Amplifiers for Bio-Potential Measurements Manufactured With a-IGZO TFTs on Flexible Substrate

“…It has been observed that the model in [21] tends to overestimate the drain current due to contact effects. For this reason, the contact model described in [23] has been added to the simulation model, and its parameters have been In order to model the electrical characteristics of double gate TFTs, an approach similar to [24] has been followed. It has been observed that the TG bias modifies the transfer curves in two ways: a threshold modulation for negative TG bias, and a modulation of the on-current for positive TG bias.…”