Detailed investigation of the conducting channel in poly(3-hexylthiophene) field effect transistors

Hauff, Elizabeth von; Johnen, Fabian; Tunç, Ali Veysel; Govor, L. V.; Parisi, J.

doi:10.1063/1.3488607

Cited by 19 publications

(13 citation statements)

References 31 publications

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“…gFPP was in general applied to the case of pentacene57, 196 or other evaporated small molecules devices in the field of organic FETs,197 and then successfully employed with various solution processed FETs 67, 75, 89, 198. In the previously described evolved methodology, gFPP is especially powerful as it allows an almost direct extraction of R C in all the OFET configurations, although it requires the careful fabrication of probes integrated in the device and a patterned gated area.…”

Section: Contact Resistance Extraction Methodsmentioning

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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Section: Contact Resistance Extraction Methodsmentioning

confidence: 99%

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

2012

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“…The field effect mobility (

μ_{normalh}^{O F E T}

) and the threshold voltage ( V th ) can be extracted from the OFET characteristics. The threshold voltage in the planar structure is the voltage at which accumulation occurs in the channel and the conductive pathway is formed . In Fig.…”

Section: Resultsmentioning

confidence: 99%

Hole‐mobility limits for the Zn(OC)₂ organic semiconductor obtained by SCLC and field‐effect measurements

Landi

Tunç

Sio

et al. 2016

Physica Status Solidi (a)

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The hole mobility of a semiconducting film with a new type of small molecule has been determined by electrical characterization with two different device geometries. The small molecule, namely Zn(OC)2, consists of oxadiazole groups (O), that act as electron conductor and blue emitter, and carbazole groups (C), that are hole conductors, which are arranged around a central Zn‐atom. This disordered organic material has in principal ambipolar conduction properties. In both the organic devices investigated, that is, a vertical diode and a bottom‐gate organic field effect transistor, the transport is dominated by holes. In the diode structure, the charge carrier transport shows a dependence from the electric field with a space charge limited current characteristic. The hole mobility value is several orders of magnitude higher as compared to the one extracted from the characteristics of the organic transistor. This large difference in the charge carrier transport properties for the two different device configurations is due to the strong influence of the dielectric/semiconductor interface which degrades the hole transport in the organic field effect transistor.

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“…For ideal OFET output characteristics, the channel current dominates. In the case of a decreased bulk resistance of increased charge injection into the bulk, the bulk current can begin to dominate, and a deviation from ideal OFET output characteristics is observed 29. We interpret the results here as a demonstration that a high PDI, that is, a high degree of disorder in the channel of the polymer OFET, leads to an increase in the relative contribution of the bulk current compared to the channel current, leading to a deviation from the ideal output characteristics in the OFET.…”

Section: Resultsmentioning

confidence: 99%

Influence of molecular weight on the short‐channel effect in polymer‐based field‐effect transistors

Tunç

Ecker

Doğruyol

et al. 2011

J Polym Sci B Polym Phys

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In this study, we demonstrate how the intrinsic properties of a polymer can influence the electrical characteristics of organic field-effect transistors (OFETs). OFETs fabricated with three batches of poly[2-methoxy,5-(3 0 ,7 0 -dimethyl-octyloxy)]p-phenylene vinylene (MDMO-PPV) were investigated. The properties of the polymers were initially investigated using Fourier transform infrared spectroscopy (FTIR), impedance spectroscopy (IS), gel permeation chromotography (GPC), and cyclic voltammetry (CV), respectively. The structure and purity of the polymer batches were found to be very comparable, but the molecular weight (M n and M w ) and polydispersity (PDI ¼ M w /M n ), varied between the samples and the HOMO and LUMO levels of the polymers were found to depend on the molecular weight properties. OFETs were then fabricated with the polymers and electrically characterized. It was observed that the channel current and the field-effect mobility increase with increasing polymer molecular weight. The output characteristics of the transistors, on the other hand, were found to depend on the PDI of the polymer. Saturation of the channel current occurs at higher source-drain voltages and short-channel behavior was observed to start at longer channel lengths for polymers with a higher PDI. This behavior is observed to be thickness dependent, and the shortchannel behavior was more pronounced for thicker MDMO-PPV films. These results are explained in terms of influences of chain packing and ordering and high bulk currents on the FET output and transistor parameters.

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Detailed investigation of the conducting channel in poly(3-hexylthiophene) field effect transistors

Cited by 19 publications

References 31 publications

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

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

Hole‐mobility limits for the Zn(OC)₂ organic semiconductor obtained by SCLC and field‐effect measurements

Influence of molecular weight on the short‐channel effect in polymer‐based field‐effect transistors

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Detailed investigation of the conducting channel in poly(3-hexylthiophene) field effect transistors

Cited by 19 publications

References 31 publications

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

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

Hole‐mobility limits for the Zn(OC)2 organic semiconductor obtained by SCLC and field‐effect measurements

Influence of molecular weight on the short‐channel effect in polymer‐based field‐effect transistors

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Hole‐mobility limits for the Zn(OC)₂ organic semiconductor obtained by SCLC and field‐effect measurements