Organic transistor model with nonlinear injection: Effects of uneven source contact on apparent mobility and threshold voltage

Simonetti, Olivier; Giraudet, L.; Maurel, T.; Belkhir, A.

doi:10.1016/j.orgel.2010.06.001

Cited by 33 publications

(20 citation statements)

References 56 publications

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“…(b) reveals a decrease of the apparent mobility with gate voltage. This behavior is due to high source and drain contact resistances and leads to an underestimation of the intrinsic mobility . The hump nonlinearity sometimes obtained in the transfer characteristic (shown in Fig.…”

Section: Ideal Otftmentioning

confidence: 96%

“…However, in the real world many parameters can influence the transistor threshold, and even its definition can be discussed. For interested readers some elements can be found in references 8 and 9.…”

Section: Ideal Otftmentioning

confidence: 99%

“…The phenomenological relation μ = β | U GS − U T | α is often used to describe the mobility–gate bias dependence ( β and α are fitting parameters and are sometimes considered temperature dependent). Note that a local mobility in the channel of the transistor, μ ( x ) = β | U GC ( x ) − U T | α , introduced in Eqn leads to an analytical expression of the drain current . This relation, originally developed for amorphous silicon based thin‐film transistors, is often used in OTFT compact modeling, which is outside the scope of this review.…”

Section: Ideal Otftmentioning

confidence: 99%

See 2 more Smart Citations

Transport models in disordered organic semiconductors and their application to the simulation of thin‐film transistors

Simonetti

Giraudet

2019

Polymer International

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Relevant organic thin‐film transistor (OTFT) simulation software must account for the main specificities of organic semiconductors (OSCs) in terms of free carrier density of states, transport mechanisms and injection/collection properties from/to the device contacts. Among the parameters impacting the OTFT performance carrier mobility is a key parameter. Usual methods to extract the mobility from current–voltage measurements lead to only an apparent, or effective, mobility. The value of the apparent mobility is different from the intrinsic channel OSC mobility. Although the effective mobility actually determines most of a given device performance, therefore providing a very useful technology benchmark, it does not describe the intrinsic OSC material transport properties, and may even be misleading in the route to improving the OTFT fabrication process. To obtain a better understanding of the transport properties in OSCs using OTFT electrical characterization, implementing an appropriate physical mobility model in OTFT current–voltage simulation software is mandatory. The present paper gives a review of the carrier mobility models which can be implemented in OTFT simulation software. The review is restricted to analytical and semi‐analytical physical models taking into account the temperature, the carrier concentration and the electric field dependence of the carrier mobility in disordered OSCs. © 2019 Society of Chemical Industry

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Section: Ideal Otftmentioning

confidence: 96%

Section: Ideal Otftmentioning

confidence: 99%

Section: Ideal Otftmentioning

confidence: 99%

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Transport models in disordered organic semiconductors and their application to the simulation of thin‐film transistors

Simonetti

Giraudet

2019

Polymer International

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“…In some situations, injection limitations cannot be modelled in the form of contact resistances due to their non‐linearity . This occurs when: i ) large energetic barriers are present, for instance in case of P3HT with Cr contacts, where Φ B is expected to be larger than 0.3 eV58–60); ii ) accessible site density in the semiconductor is lower than the monomer density61 and iii ) in case of low barriers, but taking into account the charge and field dependence of the mobility along the depleted contact region. The latter effect requires a strong mobility field dependence, such as the one found in the Pasveer/Coehoorn model62 where ln( μ ) ∝ E for high fields, while it is barely noticeable if the mobility has a Poole‐Frenkel dependence, ln( μ ) ∝ E 0.5 47.…”

Section: Charge Injection In Ofetsmentioning

confidence: 99%

Charge Injection in Solution‐Processed Organic Field‐Effect Transistors: Physics, Models and Characterization Methods

2012

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A high-mobility organic semiconductor employed as the active material in a field-effect transistor does not guarantee per se that expectations of high performance are fulfilled. This is even truer if a downscaled, short channel is adopted. Only if contacts are able to provide the device with as much charge as it needs, with a negligible voltage drop across them, then high expectations can turn into high performances. It is a fact that this is not always the case in the field of organic electronics. In this review, we aim to offer a comprehensive overview on the subject of current injection in organic thin film transistors: physical principles concerning energy level (mis)alignment at interfaces, models describing charge injection, technologies for interface tuning, and techniques for characterizing devices. Finally, a survey of the most recent accomplishments in the field is given. Principles are described in general, but the technologies and survey emphasis is on solution processed transistors, because it is our opinion that scalable, roll-to-roll printing processing is one, if not the brightest, possible scenario for the future of organic electronics. With the exception of electrolyte-gated organic transistors, where impressively low width normalized resistances were reported (in the range of 10 Ω·cm), to date the lowest values reported for devices where the semiconductor is solution-processed and where the most common architectures are adopted, are ∼10 kΩ·cm for transistors with a field effect mobility in the 0.1-1 cm(2)/Vs range. Although these values represent the best case, they still pose a severe limitation for downscaling the channel lengths below a few micrometers, necessary for increasing the device switching speed. Moreover, techniques to lower contact resistances have been often developed on a case-by-case basis, depending on the materials, architecture and processing techniques. The lack of a standard strategy has hampered the progress of the field for a long time. Only recently, as the understanding of the rather complex physical processes at the metal/semiconductor interfaces has improved, more general approaches, with a validity that extends to several materials, are being proposed and successfully tested in the literature. Only a combined scientific and technological effort, on the one side to fully understand contact phenomena and on the other to completely master the tailoring of interfaces, will enable the development of advanced organic electronics applications and their widespread adoption in low-cost, large-area printed circuits.

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“…As the bottom-contact structure is suited for potential measurements related to the channel charge distribution, KPFM-AM imaging has been performed on various types of organic thin film devices based on pentacene (Hallam et al, 2009;Nakamura et al, 2009;Yogev et al, 2010;Yogev et al, 2011;Li et al, 2012a,b;Celle et al, 2014;Wu et al, 2014;Yogev & Rosenwaks, 2014), poly(3-hexylthiophene) (P3HT) (Bürgi et al, 2003;Liscio et al, 2012;Kehrer et al, 2013;Musumeci et al, 2014), perylene (Luttich et al, 2012) or oligothiopene (Afsharimani & Nysten, 2012). KPFM also facilitates the characterisation of the carrier injection process at electrode/organic semiconductor interfaces by measuring an injection potential drop (Bürgi et al, 2003;Simonetti et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Development of an improved Kelvin probe force microscope for accurate local potential measurements on biased electronic devices

Bercu

Giraudet

Simonetti

et al. 2017

Journal of Microscopy

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An improved setup for accurate near-field surface potential measurements and characterisation of biased electronic devices using the Kelvin Probe method has been developed. Using an external voltage source synchronised with the raster-scan of the KPFM-AM, this setup allows to avoid potential measurement errors of the conventional Kelvin Probe Force Microscopy in the case of in situ measurements on biased electronic devices. This improved KPFM-AM setup has been tested on silicon-based devices and organic semiconductor-based devices such as organic field effect transistors (OFETs), showing differences up to 25% compared to the standard KPFM-AM lift-mode measurement method.

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Organic transistor model with nonlinear injection: Effects of uneven source contact on apparent mobility and threshold voltage

Cited by 33 publications

References 56 publications

Transport models in disordered organic semiconductors and their application to the simulation of thin‐film transistors

Transport models in disordered organic semiconductors and their application to the simulation of thin‐film transistors

Charge Injection in Solution‐Processed Organic Field‐Effect Transistors: Physics, Models and Characterization Methods

Development of an improved Kelvin probe force microscope for accurate local potential measurements on biased electronic devices

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