Contact resistance and threshold voltage extraction in n-channel organic thin film transistors on plastic substrates

Abstract

n -channel organic thin film transistors were fabricated on polyethylene naphthalate substrates. The first part of the paper is devoted to a critical analysis of eight methods to extract the threshold voltage from the transfer characteristic in the linear regime. Next, to improve electron injection and reduce contact resistance, self-assembled monolayers (SAMs) were deposited on the gold source and drain electrodes. The subsequent modification on the current-voltage characteristics of the transistors is analyzed by the transfer line method, using a threshold-voltage-corrected gate voltage. The improved performance of the device obtained with some of the SAM treatments is attributed to both a better morphology of the semiconductor film, resulting in an increased channel mobility, and to easier electron injection, which manifests itself through a lowering of the contact resistance. Interestingly, the modulation of the contact resistance exactly follows an opposite behavior to what reported in the case of p-channel devices, which brings further evidence for that charge injection is tuned by the direction and magnitude of the dipole moment of the SAM.

Interface Modification for Tuning the Contact Resistance of Metal/Organic Semiconductor Junctions

“…That is, SAMs bearing a dipole moment pointing towards the semiconductor produce a decrease of the contact resistance, while those with a dipole moment in the other direction lead to an increase of the contact resistance [30]. Again, these experimental facts are in good agreement with the energy level alignment model.…”

Comparative study on extraction methods of threshold voltage for thin‐film transistors

“…However, for the GMLE method, the mobility is assumed to be a constant. 16 Thus, the V th extracted from GMLE method displays a weak temperature independence and is lower than that from other extracted method. As a result, the GMLE method is not suitable to extract the V th in TFTs.…”

Difluorinated 6,13‐Bis(triisopropylsilylethynyl)pentacene: Synthesis, Crystallinity, and Charge‐Transport Properties

“…[42,43] Therefore, the elimination of V T by two derivations from Equation (1) allows one to be freed from the additional complications of the choice of method and voltage range for V T extraction. [42,43] Therefore, the elimination of V T by two derivations from Equation (1) allows one to be freed from the additional complications of the choice of method and voltage range for V T extraction.…”

“…Am ajor advantage of this method is to estimate the V GS dependence of m withouts imultaneous estimation of V T .S imilarly to m,t he V T can be extracted by various methods that produce potentially different values. [42,43] Therefore, the elimination of V T by two derivations from Equation (1) allows one to be freed from the additional complications of the choice of method and voltage range for V T extraction. However,t he method tends to amplify the measurement noise because mathematical derivationsa re involved (Figure 7a).…”